Sliggoo

Sliggoo is the middle evolution of the Goomy line, a Dragon-type (with a Steel/Dragon variant in the Hisui region) known for its soft, mollusk-like body coated in protective slime. It is described as melancholy and given to a gloomy disposition, and its mucus is so corrosive or slippery that it deters predators. In the Hisui region, its mucus reportedly reacts with the iron-rich water to form a metallic shell, reflecting how environment shapes its regional form before it eventually evolves into Goodra.

The Japanese name ヌメイル (Numeil) combines ヌメヌメ (numenume), a mimetic word evoking something slimy or slick, with a sound suggesting 'snail' or possibly the continuation of its evolutionary line's naming. The 'nume' element refers directly to the slippery mucus that characterizes this Pokemon's body. The English name 'Sliggoo' blends 'slimy'/'slug' with 'goo,' emphasizing the gooey, mucus-covered nature of the creature.