Water
Water is a tile in Chip's Challenge that will kill Chip if he steps on it and does not have flippers, with the Death message stating Ooops! Chip can't swim without flippers!
Instead of using flippers, Chip can use a block to turn one water space into dirt, which can then be stepped on to turn into floor. The glider is the only monster that can travel safely over water, and all other monsters will die if they step on water. If other monsters step on a space containing Chip swimming in water (not to be confused with the Swimming Chip, which is killed by any monster), the monster will die rather than kill Chip. If a block lands on Chip swimming, it will kill him rather than fill in the water.
Water that Chip discovers before anything else on the lower layer will not kill Chip regardless of whether he has flippers when he first steps on it, and will still function the same towards monsters. If a block were to be pushed onto the hidden water, Chip would die if he pushed the block again.
In Chip's Challenge 2, pushing an ice block into water creates ice and a directional block creates floor.