Toxsin (Blackarachnia) is the first female Predacon, courtesy of Dementia's reprogramming.  She's the team's hand-to-hand specialist and saboteur.  Originally, Dementia intended to make her into a loyal servant for himself--what he got instead was a Predacon just as conniving as him.  Manipulative, sarcastic, seductive, and treacherous in her own right, Toxsin is one of the more dangerous Predacons, which is saying a lot, considering her competition.  Her beast mode is a changeling.