Tiffany is an 8-year old girl that ALF meets at the hospital when he is accidentally given away to her as a toy by Mr. Foley. She initially calls him "Amanda," but ALF later reveals his true identity when she tries to dress him up like a girl.
Tiffany suffers from a terminal illness and is not expected to survive another year.
When a power outage traps Denise and ALF in an elevator, ALF helps deliver her baby. When she is thinking of a name, ALF suggests his own, only for Denise to remark that Gordon is an odd name for a girl. ALF then suggests Tiffany in honor of the terminally ill child, which Denise agrees with.
Tiffany was last seen being visited by the Tanners, who after departing Mr. Foley's cabin, stopped at the hospital prior to going home. They showed her a picture of ALF, which Tiffany comments on, but keeps quiet as Mr. Foley is working in her ward, unaware that Mr. Foley also seen ALF (having been talked out of suicide by him). Lynn directs Tiffany for one last look at ALF, who is seen waving goodbye from the Tanners' car.