Posey was a possum and fan of Sonic the Hedgehog's heroic work.
She met Tails at a Sonic-Con, and was the resident Sonic expert there. Tails was instantly smitten with her and she was intrigued during the fake story of Tails' speech at the con. When Dr. Ivo Robotnik crashed the party, Tails outsmarted Robotnik and sent him away. He was rewarded with a kiss by Posey, and they headed back to the con, while Tails pointed out to Posey that he has "more things in his speech that he needs to discuss with her". (IYF)
- Posey's design is modeled after Pogo Possum from Walt Kelly's Pogo comics.