Goomdiver

Goomdivers are diving-helmet-clad Goombas that appear in Mario & Luigi: Superstar Saga. They are found in the Oho Ocean Seabed, and are sometimes assisted by Bloopers in battle. In the overworld, Goomdivers dive down into view from off-screen in an attempt to land on Mario and Luigi to initiate a battle; this is signaled by a small circle of bubbles indicating their landing spot. Their names are a combination of "Goomba" and "diver".

Goomdivers appear very similar to the Aqua Kuribō from Super Mario Land 2: 6 Golden Coins.

Battle
Goomdivers will attack by either charging directly at Mario or Luigi, which is countered by jumping, or swimming upward and slowly drifting towards one of the Bros., which is countered with the hammer. If they use the latter attack, they will remain elevated, rendering them immune to ground-based moves and Bros. Attacks.

Names in other languages
Tauch-Gumba SubGoomba