8. Fused

Complete story — includes the ending

Ben is attacked in the dead of night by Ra'ad, the last of the Andromeda aliens, but Ben defeats him. Captured in the abandoned military base at Los Soledad, Ra'ad reveals that Aggregor recaptured the other four aliens and blames Ben for it. Ra'ad asserts that the Ultimatrix led Aggregor to the other aliens, and attacks it in an attempt to deactivate it, causing an explosion and vanishing. Ben and his team are subsequently attacked by Aggregor, whom Kevin realizes is an Osmosian - the same species as Kevin's father, and thus possessing the same power to absorb energy that Kevin has. Ben transforms into a new alien form named Ampfibian, an Amperi who is the same species as Ra'ad, and is trapped in his alien form; he realizes that he and Ra'ad are sharing their consciousness. Fleeing from Aggregor to Kevin's garage, Kevin is able to split Ben and Ra'ad, but Ra'ad flees as Aggregor arrives. Aggregor defeats Kevin and Gwen and nearly kills Ben, but Ra'ad intervenes out of guilt and electrocutes Aggregor. Kevin's garage explodes, and Ra'ad is recaptured, but Ben vows to use the powers of the Andromeda aliens to rescue them. Ultimatrix alien debuts: Ampfibian