What is this on my GSP

[wasabi bean]

I have had this GSP for a while now and has never seemed to do much and now it has grown a white spongey looking thing on it, i didn’t know whether they could shed or not like mushrooms and wanted to know whether this happened to anyone else? I have added a photo below but do say if you need other ones. Thanks!

 

[carri10]

Tough to see well, but I’d say bubble algae.