Worm or brain like growth on glass?

[Mikevipe]

Hello

I have an established tank with no new additions to it other than water changes for the last year+. Suddenly I am getting these brain like growths all over the back and side glass and I have no idea what it is.

Any help identifying it would be appreciated.

 

[Hemmdog]

Hello

I have an established tank with no new additions to it other than water changes for the last year+. Suddenly I am getting these brain like growths all over the back and side glass and I have no idea what it is.

Any help identifying it would be appreciated.

Your snails have been doing the dirty

 

[KJ]

Cerith snail eggs.