Major Story Arcs
Rhyme and Reason/ Double Identities
While at work at Leesburg Hospital, Mattie is called in for special case. What she assumed is a DOA case is really, Cutter Sharp hiding under a cover. He surprises her and asks her to marry him. Before Mattie can say yes, Bizarro Supergirl crashes trough the ceiling and begins chasing the couple. They are able to lose Bizarro Supergirl when she is hit by a train while on a pogo stick.
In Other Media
Mattie appears in the episode "Coldhearted" as a young doctor from Boston. Kid Flash attempts to flirt with her, but is shot down. She was voiced by Cree Summer.