Code: class UP extends Task{ public $Sword; public $Clock; public function __construct(Sword $Sword){ $this->Sword = $Sword; $this->Clock = 200; } public function onRun(int $currentTick){ $this->Sword->Clock(); } } Code: public function Clock(){ $this->getServer()->broadcastTip("{$this->Clock}"); //<---- here is line 63 $this->Clock--; } it says "Undefined property: sword\Sword::$Clock" (EXCEPTION) error at line 63.