Micromelo undatus, common name the miniature melo, is an uncommon species of small sea snail or bubble snail, a marine opisthobranch gastropod mollusk in the family Aplustridae.

[1] This species occurs in the Caribbean, Florida, Costa Rica, Panama, Bermuda, Brazil,[2] Cape Verde Islands, Canary Islands, Ascension Island, Eastern Atlantic, South Africa, Japan, Thailand, Bali, and the State of Hawaii.

[3] The large, colorful body is blue with white spots.

Minimum recorded depth is 0 m.[3] Maximum recorded depth is 5 m.[3] It lives on soft substrates and on the algal turf areas of rocky reefs.

This snail feeds on cirratulinid polychaete worms.