Maybe Phalanx is suddenly dragged back to memories of being a toddler, being unwillingly wrangled by much bigger, bullying humans. Maybe all of the memories filling Phalanx's head just happen to be from souls who'd never had the experience of wearing civilized clothing.

Whatever the reason, when that shirt shoves down over Phalanx's head, the creature seems to... panic. Just a little bit.

Luckily, said panicking is completely ineffectual, mostly just resulting in a startled gasp and a round of aimless arm-waving and pathetic full-body wriggling.

If Robin has ever wondered what it would be like to try and dress a giant, flopping, half-dead fish, he now has an educated guess.