Dear Spigot, since a long time, my players had seen a bug with the WitherBoss. First of all when they summoned him (Commonly, he doesn't move) but here he can fly wherever he wants and he can attack players. Moreover when wither hit an entity like players on animals(Commonly, he gives the wither effect) but here he didn't.

Please fix that in time :x
I do a video here: https://www.youtube.com/watch?v=73EiToRb39I