TNT Duper

Factors needed: 2 TNT, 4 Slime Blocks, 1 Piston,
1 Lever
———{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}
Flying
At the beginning of each upkeep, deal 3 damage
to target creature. If there are no creatures, target player is dealt 3 damage instead.