We have alternate forms on different environments, this is  grom_pe when he enters the water.
Some steps overlap in the representation of this transformation. The yellow underside is long gone before the tentacles begin to form and then spread, that means, there is a distinct period when Grom is just one long full-blue mouthless snake with green rings, something that isn't pictured here. Each step has it's own time, to save panels a lot of stuff is drawn as if happening at the same time, but they really don't.

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I really dislike asymmetrical, violent, "all over the place" transformations, it is supposed to be a gradual process, in which you get to enjoy the odd, new, special feelings of each step, not looking ugly or too weird during that, only slightly more nautical with every change. I hope I transmitted here what I consider a good tf sequence. Also, sea stuff is slick clean and colorful, stop making water-type tfs disgusting.

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There is a very real reason artists don't draw suckers on their tentacles. I've poured 12 hours into this drawing, but plotting, drawing and shading the suckers alone, which are reeeeeeally cheap if you stare too much at them (they don't even have highlights), was 2 of those hours.
Originally intended to be 5 panels, but I "doubled" 3 of them. Also, wanted to show the new mouth(under the torso)'s opening process with more attention, since I like it. And maybe rubbing those tubey cheeks, feels awesome and wardy xD
Next, expect magic-space form with colorful arcane markings, or my own water-tf, hell yeah.