The “Blue Dragon” sea slug is a species of nudibranch. They are known to eat jellyfish in order to absorb their neurotoxins, which the nudibranch will use to fend off predators. :
Blue Dragon Mermaid 🧪⠀ ⠀ -Day 14 of Mermay-⠀ ⠀ This amazing creature, the blue dragon sea slug (Glaucus atlanti… | Blue sea slug, Character art, Glaucus atlanticus
R/deepseacreatures - The Blue Sea Dragon, a species of small, blue sea slug. It is able to swallow the venemous nematocysts from siphonophores such as the Portuguese man o’ war, and store them in the ...