It may be an intentional system, but the character died in the final boss battle for some reason even though it was in Prism Mode.
Sadly, no, I don't have illustrations of them. I'll see if I can throw together some larger-scale pixel art or something to show them in more detail.
And yes, that's intentional. The player can still be hypnotised by the final boss and get a Game Over even if they're playing in Prism Mode. Might be a bit harsh, but I didn't think if it would make sense for the hypno-bullet to do nothing.