Icecap is encountered before Snowdrake in the Snowdin region, and is extremely hostile towards the player.
Icecap shows off the hat it seems to be wearing, though it is much more harsh than in Undertale. It will bully and harass the player for their lack of a hat, or that it thinks their hat is "God awful."
Icecap summons a series of its own hat and fires them at the player. They split open and shoot giant laser beams. This is a slowed down version of Sans' Gaster Blaster attack. Icecap summons a series of waves, which move extremely quickly and slow down, reverse, or speed up at random intervals.
The player can compliment Icecap 5 times to bore icecap, causing it to leave. They can also attempt to steal its hat, to which the player fails, causing Icecap's attacks to become deadlier.