Underworld's Consumption

Destroy target untapped creature. If the creature
has any +1 +1 counters on it, place the counters
on any Demon creature you control.
If the creature had more power than the most powerful Fiend you control, put +1 +1 counters
on that Fiend until their power is
equal to the target creature's.
"Oh no"
-Geoffrey The Virtuous