that's exactly what i thought but i'm not sure, it does have the same attack pattern though

Officially a "Rotten Mushroom". Zombie Shroom seems like a better name though. https://www.mariowiki.com/Rotten_Mushroom

It’s cool and all but I doubt that’s a reference. It’s more so just an evil mushroom counterpart like in the lost levels

Zombie Shroom, Rotten Shroom, Poison Shroom... Why do they make up a different kind of 'bad shroom' every time they make a harmful equivalent to the super mushroom?

well Poison Shroom doesn't come after you so it's different. But Zombie and Rotten seem to be identical. I do wonder if it's an agreement with Intelligent Systems that restricts them from bringing the unique Paper Mario characters/items over to the Super Mario world. Or it could just be the SMM2 designers happen to come up with the same concept by coincidence.

because they can