Elasti-Girl (also known as Rita by her teammates) is a member of the Doom Patrol, the quirky superhero team that took Beast Boy into their ranks before he joined up with the Titans. Elasti-Girl is able to grow to incredible size to gain the upper hand in battle.
She is one of the founding members of Doom Patrol, and Mento's wife. She is second in command. At some point in the team's history, Elasti-Girl and Mento adopted Beast Boy as their son. A short while, she accompanied her team on a mission to stop the Brotherhood of Evil's black hole generator and thus witnessed Mento scolding Beast Boy for going against an order.
Sometime later, they found the Brotherhood but got ambushed by them and captured. The Brain attempted to crush Elasti-Girl, but the Titans saved her and the rest of the team. After they beat the Brotherhood, Mento initiated an argument on whether Beast Boy should leave the Titans behind to help chase down the Brotherhood of Evil, with Rita arguing with Starfire.
Elasti-Girl helped Beast Boy accept each of their team member's sacrifices until it came to just herself, Mento, and Beast Boy. The trio tried to go under a rocky bridge, but it collapsed so Rita used her powers to hold it up, promising Beast Boy that she'd be fine; however, a part of the rock was shot causing the whole thing to apparently crush her to death. Luckily though, the Teen Titans saved her.
Elasti-Girl helps fight the Brotherhood and catches Beast Boy after he falls from the control panel on the black hole generator. After the Brotherhood is apparently sucked into a black hole, she shares a heartfelt goodbye with her adopted son, calling him by his name, Garfield.
Elasti-Girl served as a mother figure role to Beast Boy when he was still a Doom Patrol member, and is usually the first to show disagreement with how Mento treats him. She seems to be the only one Mento regards higher than his own duties as leader and superhero, and a heavily implied romantic interest is between the two. Elasti-Girl shows to be like Starfire by always showing compassion and consideration for others, and they're the girls of their own team that always have a big heart.
When Beast Boy was still in the Doom Patrol she often got him out of trouble whenever he messed up a mission. She acted like a mother to Beast Boy and even knows his real name. She once told a story on Beast Boy's birthday about how she read to him at night and would kiss him good night as well. Since she and Mento did not have any children she treated Beast Boy as her own even though they are not related by blood.