Flesh Grinder

Hammers remove background walls and shape blocks into half blocks and slopes, and hammer power decides which walls you are allowed to remove at all. This is the Crimson version of a tier the Corruption covers with The Breaker, so which one you end up holding is decided by the evil biome your world rolled rather than by any choice you make.

Do not spend coins reforging it for digging speed. Enough of the good rolls land on the same rounded value that the reforge either changes nothing or costs more than it returns. If you reforge at all, reforge for the combat stat, and even then a hammer is a poor weapon compared to anything you could be swinging instead.

It was called Meat Grinder at launch, which collided with the crafting station of the same name badly enough to force a rename.