Solved
Very odd occurrences (Bug, or maybe easter egg?)
I was at my cousin's house, so I don't have any screenshots to share, however.. A cabbage pult was randomly the PvZ cabbage pult while playing Coop roof (very curious) and, when playing i,Zombie En...
Due to context, and having the backup dancer thing happen again during endless, I do think it's just a cheeky easter egg.
Hope the Michael Jackson estate doesn't take offence this time! /j
