Whether he was in a relationship with her before or after his marriage is unknown. She has an unhealthy obsession for whales. Heinz made a Whale Translator-inator for her. After he turned it on, a whale trash-talked about him and convinced Elizabeth to dump Heinz for him. At present time, she appears to be living inside a whale. How long she has been living like this is unknown ("Perry Lays an Egg"), but it is implied that it was soon after she started dating that same whale.
Elizabeth has black hair, brown eyes and from every time shown, white pants, a blue lab coat like Heinz and magenta shirt. Dr. Doofenshmirtz thinks of her as a "beautiful girl."
Heinz taught her to hold a petty grudge against birds. He tried to use her obsession with whales to his advantage in order to win her heart. He made a Whale translator-inator so that she could hear what the whales were saying. But when the whales' songs were translated as insults to Doofenshmirtz, she took their advice of dumping him and finding a whale to go out with instead. She considered dumping him the best thing that she ever did.
Elizabeth is currently dating (and possibly married to) the whale. Her obsession for whales caused her to dump Heinz over him after the whale trashed talked him. She is now living inside of the whale.
- "Perry Lays an Egg" (First appearance)
- "Phineas and Ferb's Quantum Boogaloo" (Cameo)
- "This Is Your Backstory" (Appears in flashback(s))