this.color.setWhite(true);
// At the beginning of your upkeep, if there are four or more creatures on the battlefield, sacrifice Planar Collapse and destroy all creatures. They can't be regenerated.
TriggeredAbility ability = new BeginningOfUpkeepTriggeredAbility(Zone.BATTLEFIELD, new SacrificeSourceEffect(), TargetController.YOU, false);
ability.addEffect(new DestroyAllEffect(new FilterCreaturePermanent(), true));
PlanarCollapseCondition contition = new PlanarCollapseCondition();
this.addAbility(new ConditionalTriggeredAbility(ability, contition, "At the beginning of your upkeep, if there are four or more creatures on the battlefield, sacrifice {this} and destroy all creatures. They can't be regenerated"));
}