As an additional cost to cast this spell, sacrifice a creature.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Goremand enters the battlefield, each opponent sacrifices a creature.
As Goremand’s triggered ability resolves, first the next opponent in turn order (or, if it’s an opponent’s turn, the opponent whose turn it is) chooses a creature they control, then each other opponent in turn order does the same knowing the choices made before them. Then all the chosen creatures are sacrificed at the same time.