Set<UUID> toRemove = new HashSet<UUID>();
for (UUID creatureId :objects) {
Permanent creature = game.getPermanent(creatureId);
if (creature != null) {
if (!creature.getControllerId().equals(creature.getOwnerId())) {
creature.changeControllerId(creature.getOwnerId(), game);
}
} else {
toRemove.add(creatureId);
}
}