Definately one the Stink Horn variety fungus.
I once had a garden full of them. There was a "web" of joining roots or fungus between all of them.
They were very very difficult to remove and prevent from coming back again.
I eventually had to dig the entire garden up section by section and remove all the underground bulbs before they erupted through the soil into the air.
Once they opened to the air they had a wicked smell like rotting meat that attracted flies which I guess helped them reproduce.
What a nightmare.
My advise is remove all of them immediately and dig around to make sure there are no more nearby the ones that have come up through the ground.
Good luck.