Antithesis

You create a perfect copy of one creature that you can see. This copy appears in an unoccupied space no less than 10 feet away from the chosen creature. The copy is physically the exact same and has the same stats, however it has half the hit points of the original, and its alignment is opposite of its original, for example, if the original creature is Chaotic Good, then the copy will be Lawful Evil. If the creature is unaligned, then the copy is Neutral. The copy's only purpose is to kill its original, and can only make actions that would deal damage to or otherwise harm the original unless magically compelled not to. If this copy is not dropped to zero HP before the end of 5 turns, or if its original is not dead before the end of 5 turns, it explodes, dealing 3d10 fire damage to all creatures within 20 feet of it.