Found this creature yesterday

[jburgi]

He is about the size of a half dollar. The green part is hard. He looks like he is wearing an army helmet His skin on the outside is a bit rough. He is SUPER fast. Any ideas? I pulled him just in case....can I put him back in?

 

[bang guy]

It's a Stomatella varians. Very beneficial.
I've never seen one larger than a nickel though. That one must be a mutant.

 

[snakeblitz33]

Half dollar size is very big! And interesting! Bang Guy has it right! He's always right when it comes to ID. lol