VIDEO: Massive mushrooms sprout in Michigan family's yard

LESLIE, Mich. - When Ed Delaney told his wife he found a surprise for her. She thought she was getting flowers, but when she came downstairs he was holding something unusual.

"I walked in and his arms were literally filled with this huge, disgusting white mass," said Amy Delaney.

"I had this mushroom the size of two basketballs, and it kind of shocked her," said Ed Delaney.

A few days later, Amy found an even larger mushroom in their yard in Leslie, Mich. And then, two more of the giant masses popped up.

An expert at Michigan State University shared his insight.

"They're pretty clearly giant puffballs, Calvatia Gigantea, an appropriate Latin name for this monstrosities. And they are, to the best of my knowledge, the biggest mushrooms in the world," Jonathan Walton, professor of Plant Biology at Michigan State.

But Amy searched the Internet for pictures of giant puffball mushrooms this big and had no luck.

"I hadn't ever heard of anybody finding one this big," said Amy.

"I've never seen specimens this big before. It's pretty impressive, especially when you consider they grow up literally overnight," said Walton.

But Ed wanted to know if giant puffballs popping up were dangerous.

"Is it edible? What else can you do with this... is it worth anything?" asked Ed.

Walton says they aren't worth any money, and he wouldn't advise eating them. But mushrooms like these promote forest growth and can help keep a lawn healthy. And if nothing else, the giant puffballs will be a good conversation piece for the Delaneys.

"I had two of my friends over Friday. I told them about the mushroom, and I guess they didn't believe me, so I showed them and I guess that had second thoughts," said Madison Gomez, the Delaney's daughter.

Walton said to never touch or eat a mushroom that you aren't entirely certain is safe.

Courtesy: NBC News Channel, WILX