Giant snowman boss

If you make a 2x4x2 pillar of snow and put a pumpkin anywhere on top, it will spawn a giant snow golem. It will not destroy anything, only coat it with snow, but it will attack the player vigorously with snow blocks that each deal 3 hearts of damage. It will also have a ridiculously small head and 200 hearts of health. After you defeat it, you earn a ‘hostile snow’ block that will suffocate mobs if they step on them.