Hisuian Qwilfish

Qwilfish is a Water/Poison-type Balloon Pokémon introduced in Generation II, modeled on a pufferfish or porcupinefish. It inflates its rounded body by swallowing water, causing its poisonous spines to bristle outward, and it can spray toxins that make it loathed by fishers. A Hisuian regional form exists, which is Dark/Poison-type and notably evolves into Overqwil, expanding its role and lineage across regions.

The Japanese name ハリーセン (Harīsen) combines 針 (hari, meaning 'needle' or 'spine') with センチメートル/扇 nuance, but it most directly puns on 'harisen' (張り扇), a paper fan, while also evoking 針千本 (harisenbon), the Japanese word for the porcupinefish (puffer). This neatly references the spiky, balloon-like body of the Pokemon. The English name 'Qwilfish' blends 'quill' (a sharp spine) with 'fish,' describing its needle-covered, fish-like form.