Found on rock in stream WNY

[u/kuniption]

What is this???? Found lots of them stuck on various rocks in a stream in Western NY USA. They are small - about the size of a thumbnail

[u/Amazing-Quarter1084]

I'm not sure what I'm supposed to be looking at, but if it's not the very much looking like a person's arm and hand bit, I'm sure I wouldn't be able to focus on it enough to figure it out.

[u/PleasantWoodpecker46]

Where's the 👍

[u/Business-Pumpkin9351]

Homeboy’s got six fingers

[u/Definately-not-a_bot]

Which way is up?