Wide-eyed amazement with a tinge of fear.
That's how we's sum up the reaction of a baby to his Fisher Price ball popper toy, as documented in this amazing video by YouTube channel ToddleTale.
The thing can be a bit much for an infant, with its relentless ball-popping action and insane music. Which might explain why he looks a little bit petrified.
Still, it's awesome, and he can't look away.
Watch the little guy's priceless expression, which actually gets better as the video goes on (hard to believe, since it's pretty great from the start), below ...