Removes the collision box from the player so they can move around freely, while still retaining the armor slot and vulnerability to trains and biters that sandbox lacks.
Known issue: Sometimes melee biters, possibly only medium ones, have issues hitting a player who is standing still. Any movement seems to negate this, so it's not a major issue. Spitters and worms aren't affected at all.
Possibly incompatible with any mod that makes the (completely and utterly reasonable) assumption that the character will always have a collision box.