Minecraft 1.21.6-pre1
The first pre-release for 1.12.6 is out! See the changelog.
Happy Ghast
When the Happy Ghast has no players on top of itself, excluding passengers (checked every tick), it will stop moving for half a second. If there are also no passengers, the Happy Ghast will stop moving for two seconds instead. If a player rides a Happy Ghast with no passengers or players on top of it, the Happy Ghast will be able to move immediately. This behavior is implemented by the still_timeout NBT integer field, a value counting down from 40 to 0.