Popmo is a giant, living soda can with a predominantly purple "body". A jagged white stripe runs along the bottom half of the can; coupled with his glaring eyes, it somewhat resembles a mouth. He has two white gloves for hands and dark purple shoes; none of these are connected to his body by visible limbs.
In the 2.0 version of AKR2, Popmo is replaced by Shroomario, a giant mushroom monster vaguely resembling Mario. His off-white stalk is grossly engorged and dotted with small boils, with a face consisting of warped versions of Mario's eyes, nose, and mustache. His cap is red with off-white spots, similar to a Super Mushroom. His shoes and gloves are similar to Popmo's, but the former are brown instead of violet and the latter have a grey tint instead of being pure white.
- Popmo leans over and fires a soda ball from the top of his head. The ball flies straight ahead and can be easily jumped over.
- Popmo makes a large jump forward.
- Popmo lies down, retracts his limbs, and unfurls bladed spikes before rolling back and forth around the room.
- Popmo flips over and launches himself off-screen in a burst of soda. Watch the falling bubbles to know his location, and get out of the way when they stop tracking the player; Popmo will come back down with enough force to stun himself, leaving him open for attack.
- Popmo floods the room with soda, making the player slower as they were swimming. It also decreases the speed of his own attacks, but be careful of his jump; he'll return to normal speed once he's out of the soda before slowing down again as he comes back down.
- Popmo was originally designed as a can of grape soda. However, when Lambta.co was complained to about the lack of Mario theming, Popmo was changed to resemble a Mushroom in an update. The old version is still accessible in Settings.
- At the start of the level, you can go to the back of the stage and access an invisible door. Behind it are floating platforms that take you to Popmo instantly while also collecting tons of coins.
- Turning into a stone with Dragon Scale and crushing Popmo will instantly defeat him.
- When picking up a veggie. sometimes you can pick up the original Popmo’s body sprite.