At the moment I am spawning clientside blocks to a player and its working fine but I dont understand what the blockRuntimeid is. For example if I put blockRuntimeid to 0 it spawns a command block... $pk = new UpdateBlockPacket(); $pk->x = (int)$player->getX(); $pk>y = (int)$player->getY()+2; $pk->z = (int)$player->getZ(); $pk->dataLayerId = 0; $pk->blockRuntimeId = 0; $pk>flags = 0b0000; $player->dataPacket($pk); Is there somewhere a list where all blockRuntimeids are listed ? Hope you can help me. Update: It spawns random blocks everytime!?!?