It seems to me that it resembles Coprinus comatus. this one grows over straw, corn silages and similar materials. It only stay in shape for a few hours, then it soon liquify and becomes a mass of ink. When still white it is considered a delicacy, and it can be easily cultivated as many companies sell the mycelium (Fungi Perfecti for instance).
But eahamel please, don't be tempted and eat the wild ones unless you are sure of their identity

I looked it up, and yes, it does look a lot like that. That cluster was there for at least 4 or 5 days, though. Don't worry, I wouldn't eat it! It was in a public use park near my house. Close to a baseball field, by a roadway, and I don't think anything has been put on that grass in a long time, if ever. There's very little landscaping in that park and no wild areas.

Nice photo !

It's a convention!