(Episode begins with Mordecai and Rigby leave the nursery, holding a lemon tree. Rigby ties the tree to the golf cart)

Mordecai: Dude, hurry up! Tie it down, we're gonna be late!

(Mordecai and Rigby jump inside the golf-cart and drive off. A car stops)

Rigby: Go, Go, Go! Take that street! (they make a sharp turn)

Mordecai: We're not gonna make it, we're not gonna make it!

(Meanwhile, Benson and Skips are standing around at the park. Benson checks his watch)

Benson: I knew it. I knew they'd be late.

Mordecai: This is gonna be close.

(Benson and Skips watch over the hill for Mordecai and Rigby, but they're not coming)

Benson: That's it.

(Benson and Skips approach the cart before M&R suddenly come up driving)

Mordecai: (gasps) Dude, we made it! Dude, we made it! (M&R suddenly hit a rock, sending them out of control. They hit a lamppost, which the tree is lodged into. Mordecai tries to get it out, but the leaves fall out. M&R pick up the broken tree anyway and show it to Benson and Skips) Here's the lemon tree you asked us to pick up.

Rigby: Right on time. (Benson watches the sole lemon fall off the tree) I think the guy sold us a lemon, know what I'm sayin'?
(M&R snicker. Benson turns red, growls at them, upset and angry that they failed their job, and he's about to yell, but quickly calms down)

Benson: No. You know what? I blame myself. I should've known better than to trust you two morons with such a straightforward task. You obviously need supervision.

Mordecai: (confused) Super-what-now?

Benson: (picks up walkie-talkie on the golf cart) Muscle Man, Hi Five Ghost, get down here. I need you to watch over Mordecai and Rigby.

Muscle Man: (over microphone) We'll be right there.

Mordecai: What?

Rigby: No way! (drops the part of the tree he has onto the ground in anger after hearing their names) You can't stick us with Muscle Man and Hi Five. Those guys are turds!

Mordecai: They have the combined intelligence of bread-mold. Come on, Benson. Give us one more chance.

Benson: No more chances. I'm sending you to the nursery to pick up another lemon tree. If you screw up again, I'll have Muscle Man and Hi Five supervise the next job. Then the next job, and the next. (turns red) Get it?!

Mordecai: Yes. Um, yes, sir.

Benson: I'm sure.

(Benson drives the cart as he and Skips leave)

Rigby: Aw, man!
Mordecai: Ugh, this blows. You know what the worst is?

Rigby: The smell?

Mordecai: No, dude. Those lame "my mom" jokes Muscle Man always tells.

(Muscle Man and Hi Five Ghost drive up from over the hill)

Muscle Man: WHOOOOO!!!

Mordecai: Great.

(Muscle Man and Hi Five Ghost drive in)

Muscle Man: Well, well, well. Sounds like someone needs some supervision. You know who else needs supervision? MY MOM! Haha, yeah! (Muscle Man & Hi Five Ghost hi five each other) Now get in the back so I can supervise you.

(M&R, MM & Hi Five Ghost are now in the golf cart together. Loud music blares)

Muscle Man: WHOOOOO!!! Oh, yeah. This song rocks. You know who else rocks this hard? MY MOM!

Rigby: I don't know how long I can take this.

Mordecai: I know dude but if we don't pull this off...

Rigby: Aw, sick.
(Muscle Man's crack is seen)

Muscle Man: I love this tasty lick!

Rigby: That's it! I'm jumping!

Mordecai: No, dude. Don't worry. There's the nursery. This will all be over soon. (Cart passes the nursery) Whoa! Dude! (looks back at the nursery) You just passed the nursery!

Muscle Man: Pull your panties out of your butt, bro. I know a shortcut.

Mordecai: But it was right there!

Muscle Man: Who's supervising this mission? ME, that's who! So, shut your word-hole, I'm listening to my jams.

(Cart stops in the middle of a forest)

Mordecai: What? Where are we? Why are we stopping?

Muscle Man: It's lunchtime, (points to taco stand) This place has the best tacos in the city. (chuckles) You know who else has the best tacos in the city?

Rigby: Dude, Benson will blow a fuse if he finds out we were slacking off.

Muscle Man: You know who else would blow a fuse if she found out we were slacking off?

Mordecai: We don't have time for this.

Muscle Man: You know who else doesn't have time for this?

Mordecai and Rigby: UGH!!

Muscle Man: You know who else says "Ugh"? MY MOM! Hyah! (MM & Hi Five Ghost hi five again)

Mordecai: Can we please get lunch after we pick up the tree?

Muscle Man: No can do. Hi Fives has gots to have his tacos. Watch this. (picks up walkie-talkie) Hey, Benson, we're gonna pull over and grab some lunch. That cool?

Benson: (over microphone) Go for it. I know you guys will get it done.

Mordecai and Rigby: Whoa!

Rigby: Benson is never that cool with us!

Muscle Man: What? Don't you guys check in?

Mordecai: Uh, no.

Muscle Man: You gotta check in. Benson's the boss. He needs to know where you are at all times. WHOOOOO, LET'S EAT!

Rigby: How come you never check in? (Mordecai pushes Rigby away)

Taco Guy: Muscle Man! H.F.G.! (Taco Guy hi fives Hi Five Ghost) I haven't seen you guys in ages. Who are those losers? (M&R stand there)

Muscle Man: Just some chumps I'm supervising. I gotta make sure they're doing it right.

Taco Guy: I feel sorry for you guys.

Muscle Man: You know who I feel sorry for? MY MOM!

Taco Guy, Muscle Man and Hi Five Ghost: OHHHHH! (Muscle Man shakes the stand)

Rigby: OHHH! (Mordecai punches him) Ow!

(MM, Hi Five Ghost and the Taco Guy laugh)

Taco Guy: Here's a round of tacos for makin' me laugh.

(Taco Guy hi fives Muscle Man)

Mordecai: Aw, what? You actually thought that was funny?

Rigby: I guess Muscle Man is really insulting himself.

(clock transition to the forest, moments later. Muscle Man is drinking a soda)

Mordecai: It's getting late. Shouldn't we be at the nursery by now?

Muscle Man: (Stops drinking his beverage) Relax, Hi Fives is on it. (Hi Five Ghost opens the engine cover) He knows how to hot-wire the cart, to make it go crazy-fast. You know who taught Hi Fives to hot-wire the cart to get away with slacking off at work and not get in trouble with his boss? (pauses) My uncle, John. He's a mechanic.

Rigby: ...That's cool.

Muscle Man: You know who taught him? MY MOM! YES! (MM&Hi Five Ghost hi five each other a third time. M&R look at each other and get on the cart) Let's ride, babies!

(Later, they're all in the cart together as Muscle Man disobeys a railroad sign and jumps right over a moving train)

Mordecai: The road's back there!

Muscle Man: Don't tell me where the road is, baby. (drives into puddle, over a rocky road, runs over traffic cones and jumps the car again)

Muscle Man, Hi Five Ghost and Rigby: WHOOOOO!

(they pass a police car. The cop watches. The golf cart is reflected on his sunglasses. He drives up to the golf cart)

Police Officer: Yo, Muscle Man! You know how to break the law in all the right ways!

Police Officer and Muscle Man: (hi five) WHOOOOO! WHOOOOO!

Mordecai: What was that?

Rigby: This is awesome!

(the cart stops at the nursery)

Muscle Man: We're here. (clock transition to M&R lifting up a lemon tree inside the nursery) What are you doing? You're trying to throw your backs out? You don't lift it like that. That's what Bobby's for. Hey, yo, Bobby! (Bobby appears) Bobby here lifts like a champ. (short silence) Hey Bobby, you know who else lifts like a champ? MY MOM! (Bobby laughs, hi fives Muscle Man and picks up the tree)

Mordecai: What?

Rigby: Dude, I think Muscle Man and Hi Five Ghost are actually kinda cool.

Muscle Man: Lift with the legs, Bobby! The legs! Like my mom!

Bobby: (laughing) You killing me, man!

Mordecai: Yeah, I don't know about that. (cut to the road) Well, I'm glad this is finally over.

Rigby: Come on, it wasn't--

(Mordecai looks back)

Mordecai: Dude! You just passed the park!

Muscle Man: What's the hurry, grandma? We have all day, let's have some fun.

Mordecai: Ugh!

Rigby: Come on, dude, just give him a chance.

(begin a montage set to the song "Nothing But a Good Time" by Poison. It starts at the arcade, where Muscle Man, Hi Five Ghost and Rigby play Giganto-Fist. Muscle Man looks over at Mordecai, and shows him a quarter. He inserts it into the machine, which attracts Mordecai to play. Next is at the movie theater. The slime monster reaches out for the girl in the red dress. The crowd is shown, all wearing 3D glasses. Muscle Man gives Mordecai some popcorn, which he eats. Third up is at a bowling alley. Hi Five Ghost bowls a strike, and the gang all cheers for him. Muscle Man and Mordecai hi five each other several times, followed by one final four-way hi five. The montage ends with Muscle Man driving the golf cart)

Mordecai: Dude, Muscle Man's pretty cool. All except for those "my mom" jokes. Dude, I'm gonna to say something.

Rigby: No, don't! Don't try to change Muscle Man, it's not cool!

Muscle Man: Hey, guys. I haven't had quality bro time like this in ages. We should do this all the time. I know I mess around a lot, but you guys are the best. (pause) Hey, Mordecai, you know who else messes around a lot? (Mordecai frowns. In slow motion, Muscle Man says it:) MY MOM! (laughs)

(Mordecai, annoyed, by yet another "my mom" joke, finally having enough.)

Mordecai: (angry) Dude, you're saying it wrong.

Rigby: Mordecai!

Muscle Man: (confused) What was that, bro?

Mordecai: Muscle Man, that joke doesn't make any sense. Whenever you say stuff like that, you're making fun of your own mom. (Hi Five Ghost starts freaking out) It should be "your mom", not "my mom".

Muscle Man: (reflects in mirror; confused) What do you mean?

Mordecai: Well, for example, you know who else has a gap in their teeth? YOUR MOM! (A distressed, Hi Five Ghost tries to stop him; only to be ignored by Mordecai) Or, you know who else is prematurely balding? YOUR MOM! Rigby, help me out.

Rigby: (thinks) You know who else finds their clothes in the garbage? YOUR MOM!

Mordecai: You know who else lives in their car? YOUR MOM! (Muscle Man looks around, visibly frustrated, starts fuming)

Rigby: You know who else has fat ankles? YOUR MOM!

Mordecai: You know who else can't tell a--

Muscle Man: (furious) AAAUUUGGGHHH! (brakes) Are you making fun of my mom?! You're making fun of my mom! No one makes fun of my mom!

Muscle Bro (John): (over microphone) Yo, little brother! My ears are ringing! Is someone making fun of our mom?

Muscle Man: Yeah, they are, bro.

Muscle Bro: (over microphone) Oh no, bro!

Muscle Man: I know, bro!

Muscle Bro: (over microphone) That's it! I'm coming up there! (M&R get scared)

Muscle Man: You ladies are about to wish you were never born! GET OUT OF THE CART! (M&R do so) You're gonna get it! Nobody makes fun of my mom! Nobody! (he huffs and puffs. Then, all of a sudden, the ground splits. A burning truck emerges from the ground. Muscle Bro steps out)

Muscle Bro: Which one of you girls was talking about my mom? (points at Rigby) Was it you, Tiny? (knocks him over and goes to Mordecai) Or you, string-bean? (pushes him, too)

Mordecai: We were just--

Muscle Bro: So it was both of you!

Muscle Man: I think they hurt mom's feelings, bro.

Muscle Bro: You hurt our mom's feelings. (lifts up a picture) Pay her a compliment, tell her she's beautiful. TELL HER!

Mordecai: (shakes in fear and horror) Uh, you're beautiful, Muscle Man's mom.

Muscle Man: Now, kiss the photo and tell her you're sorry. (John holds photo to Mordecai's face)

Mordecai: Sorry. (kisses photo)

Rigby: (kisses photo) Sorry...

Muscle Man: Fire up the grill, bro. (John puts a grill on the ground, lights it ablaze, and Muscle Man comes up to put the photo on the grill. John flips it, and then hands it to Muscle Man) Eat this picture of our mom, or you'll be sorry!

Mordecai: Please, don't make us eat the picture...

Muscle Man and Muscle Bro: EAT IT!

(Muscle Man rips the photo in half, then hands the halves to M&R. Shaken by the wrath of two muscle bros, Rigby bites into his half first, then Mordecai. Muscle Man and John laugh at them)

Muscle Bro: You should have seen the look on your faces!

Muscle Man: We got you good!

Mordecai: What?

Muscle Man: It was all a prank and you chumps fell for it! (they hi five each other and laugh once again. Hi Five Ghost comes out of the bushes to hi five Muscle Man) That's not even a picture of my mom, (M&R put the two halves together) It's a picture of my butt cheek! I just squished it up to look like a woman's face.

Mordecai: (as M&R are disgusted) Aw, sick!

Muscle Man: Are you still hungry? Cause I got multiple prints. That's right. I dabble in photography. (MM & Hi Five Ghost, as well as John, three-way hi five. Clock transition to the park)

Benson: Thanks for picking up this tree. I knew I could trust you two. (to M&R) As for you two, next time I ask you to do something, do it right or I'll have them supervise you again. Got it? (Benson and Skips walk off)

Muscle Man: You know who else is going to have to get supervised again for not doing it right? (He's seen twirling his shirt around while on top of the cart) MY MOM! (Hi Five Ghost starts driving the cart around) WHOOOOO! Later, ladies! (they drive off, leaving M&R incredibly furious)

Mordecai: (annoyed) I really hate Muscle Man.

Rigby: (also annoyed) You know who else really hates Muscle Man?

(Episode ends.)