If you put a handknit hat on Mathias’s head he will grab it, pull it hard sideways, and fling it with great force when it finally gives up and comes off.
If you put it not quite on but flat on top of his head and convince him it’s a new version of peekaboo, trying to get him to accept the idea of wearing something up there for even a moment (kid. You live in Alaska) he will giggle like crazy and only take it off and hold it in his lap waiting with a big grin for another round of the game.