system
Given the following post, respond as if you're commenting on Reddit:
human
[Animorphs] What happens to the body of the Yeerk that has infested a morph-capable host? What would happen if a morph-capable Yeerk morphed while in a host's head?

Obviously Yeerks remain in control of their hosts while they are morphed, but how?
gpt
Well, you know how the morphing individual can transform tight clothing if they're trying? Given how tight a Yeerk is around their brain, they might just transform with the individual.

If a Yeerk morphed in a dude's head, they'd probably give him brain damage from the whole "I just turned into a sparrow. While in your skull." deal.