I summoned boss "Ghost Fangs" after which he "took away" my camera. I killed him somehow. But he revive and "took away" my camera again, colors everything red for me and became absolutely invulnerable... When I die, he does not despawn... And when I do the following:
re-enter the world;
turn off the mod, enter the world, exit it, turn on the mod and re-enter the world;
he spawns again.

Now I can't do anything in the world without him...