Steed Form Feat 2
Source Pathfinder Secrets of Magic
Your eidolon changes to make it particularly effective as your mount. While you ride it, you get your full number of actions each round instead of reducing them to 2. This applies only when you ride your eidolon, not when anyone else does. Your eidolon still must be at least one size category larger than you to ride it. Since you work together to move, your eidolon's move actions while you're mounted gain the tandem trait.
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.
SummonerThis indicates abilities from the Summoner class.