This idea has been on my mind for a long time and I'm honestly surprised it's not a thing yet.
The Bloodmoon skinline has a lot of elements from japanese culture and especially the masks are Oni (jap. demon) based.
Oni are often depicted as somewhat Ogre or troll like, which really lends itself well to Trundle.

Lol board threat:
https://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/1AV7E4F0-skin-idea-bloodmoon-trundle