The Gravemind

This creature's power is equal to the mana spent
to cast it.
When one or more Horrors you control
deals combat damage to a player, you may
put target creature card with a mana value less
than or equal to that damage from that player's graveyard onto the battlefield under your control.
It's a Flood Horror in addition to its other types.
"We exist together now, two corpses in one
grave."