Duckman and Cornfed first encounter Tami when she is hit by Duckman's car while on roller skates. She explains her tragic background where her family was killed in a tragic sleigh accident, leaving her to continue on her own. She takes a liking to Duckman's family for appearing sweet and perfect. Wanting to help her, Beverley, filling in for Bernice during her time as a Congresswoman, allows Tami to stay in their house. Tami quickly reveals a twisted side by drugging lattes she gives to Beverly, causing her to become ill and intoxicated. When a neighbor's gardener witnesses her spiking the lattes with pills, Tami violently murders him with a trowel.
Beverly sees Tami's seeming progress with soothing the dysfunction of Duckman's homelife and is subjected to further drugging and framed for the murder of the gardener. Suspecting something is amiss, Cornfed researches Tami's past and finds that there was no accident, but rather that she slayed her family, using the sleigh story as a cover. (This also leads to the possibility that Tami set up being hit by Duckman's car.) Bernice also suspects something is amiss when she hears the answering machine's message left by Tami, openly admitting that she'll take over the family. Both Cornfed and Bernice race to get to the house but are caught up in a nasty accident when the car she's driving crashes into the bus Cornfed commandeers.
Duckman and his sons express their sadness over Beverly being arrested which drives Tami into a violent rage over their seeming ingratitude for "making them a perfect family". Although she suffers a series of horrific injuries and normally fatal accidents, such as being maimed by a ceiling fan and being electrocuted, Tami survives and comes after Duckman and his family with an axe. During this, she openly admits to having murdered her family for not being perfect and the gardener, with the implication that she might have murdered others for failing to be perfect. She returns to drown Duckman in his tub, pulling him down the drain into open water in pure cartoon fashion. Tami is eaten by a shark and Duckman's family is seemingly safe, until her hand is shown emerging from the bathtub. Aside from a cameo in the final episode, she never appears again from that point.