Golem

Golem is an enemy encountered after mining in room 730, he is a giant humanoid stone monster. His attacks take 60% of your health but slow attacking speed. The golem will be able to spawn a rock wall, instantly killing the player if the player gets pushed up to the roof of the room, this wall can be insta-mined using the pickaxe found in room 730 and every save room beyond that.

Hard mode changes
In hard mode, Golem gains the ability to charge, dealing 85% of the player's health. However, the golem will not be able to make any turns until it hits a wall or until it hits a player. Golem will also spawn walls more frequently and can be pretty annoying.