Tesla was the plant experiment preceding Vash and Knives, and is one of Knives's reasons for distrusting/hating humans in the manga. She doesn't appear in the anime at all.
Both Vash and Knives found old computer logs about her and saw the horrible experiments performed on her. She was hardly stable and was tortured without mercy from the very first day she was "born", until the cruel experiments that finally killed her.
She was found and retrieved on May 3, 2405 and grew at a rapid pace. From the day she was found, she was treated as a mere science experiment--she was dissected and treated as less than an animal. After 100 days, the crew began to question the morality of her treatment, and ten days later, they began to find tumors all over her body because of their cruel treatment. They tried to remove the tumors, but her condition continued to decline. Soon after, there was a sharp decline in her renewal functions, as she lost her hair, began to give off a distinct odor, and fractured her thigh bone upon attempting to get up. Finally, on day 229, she had a seizure while the crew gave her medication, and fourteen hours later, all biological functions "ceased." Following completion of specimen report, the project was closed.
After her death, they kept a dissected form of her body in three separate tubes. One that held her right arm, one that held most of her body, and the other held her brain and eyes.