You sprawl as much as you can in the small pool, letting your eight long legs spread out as much as they can in the cramped pool. Three of your tentacles don't even fit completely inside, and you fidget with them idly as you submerge yourself enough to breathe the toxic water. You suppose that you're a fairly decent size for an octopus-monster, especially since the ones in biology class that you've seen were about the size of your hand. You've still got most of your torso, and each tentacle is about three times as long as your original legs were. Being completely human above that, albeit with yellow skin and black blotchy marks, probably looks pretty weird, if not downright stupid.
You lift one of your 'arms' that are lying out of the water to feel your face and head again. You didn't notice earlier that your hair had fallen out when you were octo-morphed, but at least you're a bald octo-thing. Hair on an amphibious octopus would have been REALLY stupid looking.
Ah, well - enough introspection for now. Onwards!
You struggle on, resting in small pools that have collected whenever you can. By the time you finally pull your eighth tentacle up to the top of the hill with the industrial waterfall, the sun has moved perceptively across the sky since you first entered the park. The exhausting climb took at least three hours, maybe a little bit longer, but at least you're finally at the top!
While you're catching your breath, you idly notice how the toxic waste has not caused any further mutations after the initial change. Your body size, shape, and leg count seems to be stable, which you hope is a good thing.
Are you ready to enter that industrial drainpipe to try and find the answers you seek?