"He sounds disappointed, yet confused." Kyurem points out. "I'm curious about water being lethal to your species and the other species. There are Pokemon who absolutely cannot handle water, but you don't seem to have any qualities of why water is dangerous to you."
"If he's confused about the water too, then I'll explain. Both Inklings and Octolings evolved from squids and octopi respectively, both of them used to be able and even needed to live in the water, but once the sea became scarcer in time in the past after its initial growth, squids and octopi were stranded, limited to puddles dotted around. With very little living space, they underwent an evolution to become more suited for land, eventually becoming the Inklings and Octolings you see now. This came with a negative side-effect, while we adapted to live on land, our bodies became hydrophobic, thus when we become our cephalopod forms, it's to swim in ink, and not water." Coral explains. "Also, Octolings can cut off their tentacles to create an Octarian. That came as an evolutionary bonus for Octolings, as Inklings don't have the same capability."