Cross Bomb was added in Beta 50.0. Previous Versions can be found here.
As the first Bomb added after the removal of the Tribe, Cross Bomb is the first one that also doesn't sacrifice itself at the start of the turn. Additionally, it lacks a Dust as well. This also happened to Game Bomb.
Instead, it has Charge, allowing it to attack any enemy right away (if Taunt is not a factor). However, if it doesn't attack at all during the turn, the monster in front of it will take 2 DMG. This condition is identical to that of an old Elder Puzzler (but not the target).
Keep in mind that when using Perseverance, KR won't be applied from its 2 DMG effect, as it's not from an attack.