Cool Bone was added in Beta 50.0. Previous Versions can be found here.
Being an attack from Papyrus, it has a very similar effect, being able to attack more than once per turn if it attacks a monster instead of the opponent directly.
While it lacks Charge (and even Haste) and its ability only allows it to attack one more time each turn rather than as many times as it wants as long as it kills each time, it doesn't actually need to kill the monster it attacks to attack again. What this means is that you have a choice: 1 attack to any enemy, or 2 attacks limited to enemy monsters.