Starfire the Terrible is Starfire's main role in the episode, Starfire the Terrible. In order to make Robin happy, she became her archenemy(which only appeared in this episode).
Gallery
Starfire the Terrible with a smile.
Starfire the Terrible ready to finish of Robin.
Starfire the Terrible introducing herself to Robin(the bad way).
Looks like Starfire the Terrible destroys something else besides Robin's head gel.
R U mad, girl?
Starfire the Terrible ready to introduce herself to Robin.
How should I do my evil laugh?
Something shock her, but what?
Starfire destroy 99.9% of Robin's head gel.
Introducing herself to Robin.
Cyborg is mad after Starfire's action.
Videos
Teen Titans Go! - Starfire has a crush for Robin
Start at 0:22
Teen Titans Go! - Hilarious Montage Part 4
Start at 7:50
Trivia
She caused Cyborg's fifth death Raven's second death and Beast Boy's second death.
But, since that Cyborg, Raven and Beast Boy appear unharm in the next episode, Starfire the Terrible's debut could be non-canon.