Shadowy Figure from "T.K.O." is the one creeping around the Bodega.
The same mysterious flashback from "We Messed Up", "Know Your Mom" and "Face Your Fears" plays when K.O. asks Mr. Gar why he left P.O.I.N.T.
The door in the sewer leads to the room with the glorbs from "Do You Have Any More In The Back?"
Nice Job Breaking It, Hero!: When K.O. sees Shadowy Figure entering the pipe underneath the plaza, he abandons his post and chases after him, ignoring Gar's instruction to stay put. When K.O. chases him to a door and doesn't see him, he assumes that Shadowy had entered through the door and breaks it down. It turns out that Shadowy Figure wanted K.O. to break down the door, as he couldn't get it open himself, so he could enter it to take all the glorbs.
Shout-Out: In the beginning, where Mr. Gar calls for an employee meeting, Enid replies "What's the matter Mistah G?" in a Harley Quinn impression.