You can briefly transform yourself into a second form, acquiring its physical qualities.
Prerequisite: Exposure to Alter Self spell.
Benefit: Choose one specific form that you've turned yourslef into with the alter self spell. Once per day, you can use alter self as a spell-like ability to turn yourself into this form for 1 minute.
Special: You can gain this feat multiple times. Each time you take this feat, you can either extend the duration of an already chosen alternate form by 1 minute or choose another specific form from among those you've experienced after casting alter self on yourself.
Source: Unearthed Arcana