Bat (Mario Kart 64)
Bats are creatures that appear in Banshee Boardwalk in Mario Kart 64. Specifically, they appear in the abandoned house area, where clouds of them fly out from a pair of coffins. Unlike other obstacles in the game, hitting them simply causes the racer to slow down rather than spin out, while the bat disappears in a star-like effect. They are not present in time trials of the course, likely due to the fact that time trials in the game are invalidated by hitting walls or obstacles, with the bat cloud being so thick as to be fairly difficult to avoid the bats.
In the Mario Kart DS iteration of the course, they are replaced by Swoops. Unlike the generic bats, the Swoops are present in the Time Trial mode, likely due to this game not having the issue of hitting obstacles negating record-keeping.