Enemies spawn 1-2 floating bones on death, which block enemy shots and damage/repel enemies that touch them.
Bones block 2 shots and/or deals 2 ticks of damage before breaking.
Bones deal contact damage equal to Isaac's damage in the moment they were created.
Notes
Bone particles will be created whenever Isaac shoots, though this is purely visual.
Because the bones deal contact damage equal to Isaac's damage in the moment they were created, if the damage stat was changed, the bones that were already present on the screen will use Isaac's old damage stat.
The bones can immediately hit splitting enemies' spawns, damaging or destroying them as well.
A bone spur is a bony growth that often occurs close to joints and can have a multitude of causes from joint damage from osteoarthritis to excessive overuse of said joints.
Bugs
Bug!
If switching between Tainted Lazarus and Dead Tainted Lazarus with the Flip item, there is a chance to spawn a mass amount of bone spurs on the place you flip each time you use the item.
BFFS!: Doubles the bones' size and damage.
Spin to Win: Boosts the bones' damage while spinning even though there's no visual tell of the effect.
E. Coli/
Flush!: Enemies that are turned into poop don't spawn bones.
Bug!
Tainted Lazarus and 
Dead Tainted Lazarus with the 
Flip item, there is a chance to spawn a mass amount of bone spurs on the place you flip each time you use the item.
Bones 
The Forgotten Unlocks 
Mother Unlocks 
The Binding of Isaac: Rebirth
