Nega Beast Boy shows no kindness or emotions like his counterpart Beast Boy does. His personality is sadistic, cruel, and heartless; similar to Danny's Counterpart Dark Danny. Nega Beast Boy possesses no such trait; he is pure evil and craves destruction and chaos. He is effectively beast boy worst enemy, and is willing to kill to get what he wants and even provoking Beast Boy which he likes to torture him as he mentions his ex girlfriend Terra in front of Beast Boy which he reminded Him Saying no wonder why she dumped him which shows he can be cocky like Dan
Since Cyborg, Starfire and Beast Boy are protected to Trigon's powers thanks to the Ring of Azar, he refuses to expend more of his energy to destroy them and uses his powers to create evil clones out of each of them and pits them against each other, each against his or her own clone.
Nega Beast Boy matches Beast Boy form for form, but Beast Boy holds his own quite well. Shortly after, Nega Beast Boy taunts Beast Boy by reminding him of Terra's duplicity. Finding his weakness, Beast Boy furiously attacks his clone.
Later, as the tide of the battle above ground starts to turn against the Teen Titans, they decide to switch combatants in hopes of regaining the advantage. Therefore, Cyborg fights against Nega Beast Boy and easily beats him by a punch. He then evaporate into wisps of red energy that return to Beast Boy.
Nega Beast Boy as a cobra.
Nega Beast Boy as a wolf.
Nega Beast Boy as a woodpecker.
Nega Beast Boy as a Pteranodon.
Nega Beast Boy as an elephant.
Nega Beast Boy as a python.
Nega Beast Boy as a tiger.
Nega Beast Boy as a falcon.
Nega Beast Boy as a Spinosaurus.
Nega Beast Boy as a Smilodon.
Nega Beast Boy as a Utahraptor.
During the battle, Beast Boy turned into a Tyrannosaurus Rex and Nega Beast Boy turns into a Spinosaurus and the battle resembles to the movie Jurassic Park III.