Trista Phelps is one of the pre-made downtownies in The Sims 2: Nightlife. She can be made playable by befriending and asking her to move in, or by marrying her. Trista's career is randomized at the start of the game, and she is mainly interested in Weather, Crime, and Work.
Her name is randomized when Downtown is generated. The name "Trista Phelps" is only referenced in the game files. Like most downtownies in The Sims 2, she has a customized facial structure. Trista uses the 1st Maxis face template in Create a Sim, except the eyes use the 11th face template, the nose uses the 14th, and the mouth uses the 26th.