Flippers are one of the two "Bugs" that appear in Bingo mode of Stack-Up.
Flippers are purple spring-like bugs that consist of two feet, three rings, a backbone, two red eyes, and two antennae. When they jump to another button, they compact and then spin while they are in the air.
These enemies will only appear one at a time. Once the current one jumps off-screen, another spawns somewhere else. These enemies jump across all of the buttons in a row or column in order to make the R.O.B. move in a way that the player doesn't intend, possibly messing up the player's work. The only way to stop this is to de-activate one of the buttons they they activate, preventing it from causing that action.
- These enemies only appear in Stack-Up, and haven't made any major appearance since then, much like Spike.
- These enemies only appear in single player mode, likely because it would be too hectic to move blocks with both another player and a Flipper taking control of R.O.B. at the same time.