Certified GKH Gardening Expert
Those are mushrooms! This one belongs to the Clathrus genus.
They are useless to humans, and can have a nasty odor. They do break down decaying material quite quickly, which provides nutrients to your soil.
I would advise leaving it to continue on. They are harmless, and do a good bit for your garden soil.
Should you still wish to remove them, this article will help: