Jerry dates a girl with multiple personalities.
"It's like having another girl in bed with us every time we have sex," he brags to George. "Sometimes more. It's really becoming a chore trying to remember which one of her personalities likes what."
"Does she have a sister?" a hornily excited Kramer wants to know.
"She IS her sister," Jerry tells him.
Jerry introduces his girlfriend with multiple personalities to Elaine.
"Glad to meet you," Elaine tells her. "ALL of you."
George sees an opening and starts dating her, too.
"Where's the problem?" George tries to reason with an irritated Jerry. "I'm dating one personality. You're dating the other."
Things become complicated when Jerry finds out one of her personalities is a male.
"That doesn't make me gay, does it?" Jerry worries. "Not that there's anything wrong with that."
Jerry forgets her birthday.
"I must have given your birthday gift to one of your other personalities," he lies.
In the end, like every other woman he's dated, Jerry's girlfriend with multiple personalities begins to drive him nuts.
"Ever tried pleasing ten women at once?" he complains. "It can't be done."
The final straw comes when Jerry gets arrested.
"Who knew one of her personalities was 16?" he asks.
When he breaks up with her, he helpfully suggests, "Ever thought about dating a Mormon? You should. They're used to having multiple wives."