From New rule ! You wont get an answer, you can even get banned! But your ideea is cool! I wanna wear dirt in my case! Read here https://forums.pocketmine.net/threads/wearable-block.15790/
Wearing blocks as helmets or hats is not possible (or will look awful). Maybe that will work PHP: $player = /**player object*/;$player->getInventory()->setHelmet(\pocketmine\item\Item::get(\pocketmine\item\Item::TNT)); Even if you get it to work, the block will be shown in the player inventory helmet slot but not to other players. But you can wear pumpkins Edit: just realized @asters link