Ice
Ice is a tile that makes any moving object move without user interaction and without any control. Whenever an object steps on ice, it will slide in that direction at double its normal speed in Lynx (blocks are considered to be as fast as Chip, since they are always moved by Chip), and at 10 m/s in MS discounting slide delay, until the ice stops. The four "ice corners" will turn the object in that direction.
If Chip has ice skates, he can step on ice as if it were floor but at 5 m/s.
MS
In MS, ice corners act as two one-way thin walls: Chip can step over them from within the tile if he is wearing ice skates (or starts the level on such a tile, or is otherwise not in a sliding state while on the tile--see invalid tile and data resetting) and the move is otherwise legal.
There can be objects on ice, and Chip can pick them up without sliding.
Buried ice corners have unusual properties, stemming from the same programming that allows Chip to skate over them. When monsters or Chip start on ice corners, they can step over them, but blocks can only do so in a specific situation. The reason for this is that ice corners are mostly programmed to be transparent, but they do not act as transparent to a sliding object because it turns before the transparency takes effect.
The one exception is when Chip is sliding directly behind a block that reaches an ice corner, either because of Chip using boosting or a spring step, or the block being slowed by slide delay. Although the block is now programmed to turn, it has not physically turned yet. Chip slides before blocks, such that if Chip is within one space of the block, he attempts to push it. The Headbanger Rule does not apply because the block is currently programmed to move in the new direction, so the result is that the block is pushed as if there was nothing under it.
Usually, the result is that the block moves across the ice corner the same direction as Chip was moving and Chip continues sliding, although if this move is illegal a ram will occur instead. This behavior is termed cross-checking.
Lynx
In Lynx, Chip cannot walk through ice corners like in MS. Ice corner will always act as two normal thin walls, even if Chip wears ice skates. Boosting, slide delay, cross-checking, ramming and putting objects on top of ice are also impossible in Lynx. Blobs slide at half the speed of other creatures. If Chip starts the level on ice, he can move in any direction, but if he decides not to move, he will slide down.
Chip's Challenge 2
In Chip's Challenge 2, ice generally behaves the same way it does in Lynx, with a few differences. Melinda does not slide on ice and behaves the same way as Chip wearing ice skates. Rovers, like blobs, move at half the speed of other sliding creatures. Speed boots have no effect on sliding speed. Objects can be placed over ice, and Chip will pick them up while sliding.