Amphibious Form Feat 2
Source Pathfinder Impossible Magic
Your eidolon adapts to life on land and underwater. They gain the amphibious trait, allowing them to breathe in water and air and to avoid the normal –2 penalty for making bludgeoning and slashing unarmed Strikes underwater. They gain a swim Speed equal to their land Speed or 25 feet, whichever is less; if they're normally aquatic, they gain a land Speed equal to their swim Speed or 25 feet, whichever is less.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
EvolutionFeats with this trait affect your eidolon instead of you, typically by granting it additional physical capabilities.
SummonerThis indicates abilities from the Summoner class.