Gumboy: Not the face!
Gumboy isn’t always a rubber ball. Certain tokens, when collected, change him. Some change his substance, turning him into what the game calls “air” or “water”, although this seems to mainly just affect his density, not his resistance to deformation. (Possibly the “air” form is more vulnerable to death by puncture, like the balloon it effectively is, but I’m not entirely convinced of this.) Others change his shape, turning him into a square or a five-pointed star, which affects how he rolls (or, on a slope, resists rolling).
There’s at least one other way to change Gumboy’s shape, and it’s a little disturbing.
I said that there were no enemies, but this turns out to be not quite true. There are caterpillars. At least, they’re first seen in a level titled “caterpillars”. They’re a little too small for me to identify them clearly myself, and their behavior is uncaterpillarlike in some ways, such as the way they can jump a little. They’re capable of moving around under their own power, but tend to be basically subject to gravity anyway, sliding down slopes and getting caught in depressions. Gumboy’s repulsor field affects them, which is a good thing, because you need to get them out of the way. The caterpillars appear in a series of levels where you have to shepherd a number of glass spheres around, or possibly soap bubbles — whatever they are, they’re fragile, liable to break (and respawn at their starting locations) whenever they hit a surface too hard. They’re also killed by the caterpillar’s bite.
And caterpillars do bite. You notice this the first time you hear Gumboy’s little squeals of pain on rolling over them. What I didn’t notice at first is that they were actually eating him, from the chin up. By the time I caught on, he was downright gibbous.
Now, healing Gumboy is easy. Hitting a checkpoint seems to take care of it, as do the shape-change icons, and possibly even teleporters. I can imagine situations where being partly or even mostly eaten is even an advantage, letting you squeeze through smaller space. Nonetheless, the thought of bugs eating my face is disturbing enough that I cannot allow it. Are the caterpillars even capable of eating him completely? I don’t know, and I’m not about to find out. I’ve seen characters in videogames killed in a great many ways, including excessively gruesome ones, but this prospect is just worse somehow. I guess it shows that the decision to make him into a character rather than an inanimate object really has allowed me to identify with him.