Identification: unsure of what this could be

this is off a maple tree in Regina Saskatchewan.

Is this some cycle of gowth, parasite, or infestation?

We have tent catapillars on an elm tree next to the maple.

Thank you for looking!

 

Maple gall mites: http://wimastergardener.org/?q=MapleGallMite

 

Thanks for that link, I didn't know about Erineum gall, which is effecting a bunch of sycamores. It's not particularly disfiguring, but I was wondering if I should worry; nice to be reassured! ;)