Ice Cave with Ice Slime and Ice Zombies

Ice Caves

• New cave biome that generates under cold biomes
• Introduces icicles similar to stalactites (have a higher chance of falling, transfers water faster into a cauldron)

A new ice slime, the Ice Cube

• spawns in the Ice Cave. 
• When attacking, it slides and jumps. 
• Perhaps it drops some kind of slime snowball that does slightly more damage than a normal snowball.

A new ice zombie, the Frozen

•  Spawns at night in cold biomes, similar to Strays.
• It also has a chance to spawn in the ice caves, riding on the Ice Cube and weilding a spear.