Boga

"There there, little lizard. Stille nú, stille nú. What's got into this varactyl, anyway?" "That's Boga. She's crazy. Killed two trainers last week." "Boga? Ah, din nama is kinglich. Well, turn this poor girl free. She has seen enough of war." "Um, if you say so, Mr. Jedi." "Wait, screw that. Let's use her to chase down General Grievous, leaping recklessly across giant crevasses while battle droids shoot at her."

- Obi-Wan Kenobi and Boga's trainer, on Utapau

Boga was the maddened varactyl who spent her troubled life on Utapau, slaughtering anyone who attempted to tame her and put her in the army or the circus or something. Obi-Wan Kenobi calmed her down with a combination of mind tricks, personal charm, and Scooby snacks... then once she was passive, he used her to chase Grievous on his mechanized wheel bike, thus endangering the poor creature's life. Honestly, there were plenty of speeder bikes available he could've flagged down.

Clone troopers gunned her down during Order 66, sending her and Obi-Wan plummeting into a deep pool of water... wait a minute, that never kills anyone. She probably survived and lived the rest of her life in a nunnery somewhere.