Scientific name: Thuridilla multimarginata
Taxonomy: Kingdom Animalia → Phylum Mollusca → Class Gastropoda → Subclass Heterobranchia → Infraclass Euthyneura → Subterclass Tectipleura → Superorder Sacoglossa → Superfamily Plakobranchoidea → Family Plakobranchidae → Genus Thuridilla
Locations: Hawaii
Group: Marine Life → Invertebrates → Sea Slugs
Less than 2 mm long. This is the smallest thing I've intentionally photographed underwater.