Turtle
The turtle is a tile introduced in Chip's Challenge 2. Chip, Melinda, doppelgänger, blocks, and some monsters can step on them once, and they will then turn to water tiles.
Red teeth, blue teeth, centipedes, ants, purple balls, walkers, yellow tanks, blue tanks, rovers, and blobs can step on turtles. Gliders will step on turtles without changing the tile to water. Fire boxes and ghosts will avoid turtles. Blocks, ice blocks, and directional blocks can be pushed onto turtles and safely pushed off without needing to step on the newly formed water tile.