Because of a feather molting issue, he's got to stay out of the water but thankfully for Pierre, there's no limit on his screen time and he loves to binge watch anything related to penguins.
Every time a lobster or a cockroach is ready to size up, they have to molt, shedding their old skeleton and leaving them soft and vulnerable for days or weeks while they wait for a new outer shell to harden.
Once caterpillars finish their second to last molt before chrysalisification, their bodies release a big dose of a growth hormone that tells 'em to stop eating and look for a good place to hang out, literally, for a few weeks.
You can sometimes find the shed skins left behind by them, sitting on the tops of tall grass, or in many parts of North America, you can find the shed skin left behind by this, a cicada.
So shedding their skin seems to have something to do with how they grow, but wait a second, because we grow too and we don't shed our skins like a snake or an insect.