Amphibious
Water moves gain STAB regardless of type.
10 species 2 as main 8 as innate 6 battle AI weight, −2 to 10 — 6 is the untouched default
In detail
Grants STAB to Water-type moves regardless of the Pokemon's typing.
Types that carry it
10 species Dragon 5 Poison 4 Fighting 2 Ice 2 Electric 1 Ghost 1
As a main ability
2 speciesSelectable — one of up to three, and only one is active.
As an innate
8 speciesAlways on, alongside whichever main ability is chosen.