In both 1.12.2 and 1.7, whenever I spawn a hunter chopper on the ground, it just stays still and lags my game. eventually, the world stops responding and crashes with the exit code -805306369. It also turns your world into a corrupted void where only bats spawn, and they can’t move. It’s quite frustrating to deal with bugs, and the only solution is to load a backup of that world before you spawned it in.