For making transformations into sea polyps as found in Ursula's grotto in the Little Mermaid.
pol-tf, sea polyps, lm-p0lyp, jagged mouth, crooked body, sickly green skin, yellow eyes are some good terms to use for the standard ones seen in The Little Mermaid.
I've also trained in actual sea polyps though, and so you can add in anemone, tentacles, bioluminescent, tubular, etc. if you want something more like what actually exists in the ocean.