Happy Ghast causes lags

For whatever reason, the Happy Ghast causes severe lag when parked in a certain spot. We built a small wooden crane for our harbor, and another player parked the Happy Ghast there (tied with a rope), causing a permanent, extremely severe lag. After we moved him a few blocks (after searching for the cause in a copy world) the lag disappeared instantly (to be honest, I didn't even know that you can cause a lag with that lol).