Maybe try PHP: public function onZombieClick(EntityDamageEvent $event){$zombie = $event->getEntity();if($event instanceof EntityDamageByEntityEvent){$player = $event->getDamager();if($player instanceof Player){if($zombie instanceof Zombie){// Do something}}}} I'm not sure if this works but it should.
It does, remeber to import from entity event, not player. PHP: use pocketmine\event\entity\EntityDamageEvent;