GRAVE MATTERS event?

Good afternoon.
Xbox series S, solo play, offline exiled lands
What do I have to do to play the GRAVE MATTERS event? I’ve been to all three locations and nothing happens.

Dont play this game. You lost your progress. Game stop saving your progress in singleplayer/coop mode after few hours of playing. Don’t spend your christmas time and money. This game give you only lost your progress and no saving. This is christmas gift from this game.

You have to wait for them to pop up. When it happens take you pickaxe and destroy the temples that popped up. The boss in the bubble will now attack, kill him and a wooden chest pops ups.

Thanks for the feedback

Any weapon works.