Serena gives Larry a pill which makes him younger.
An amusing Season 8 episode. Serena is babysitting (though Tabitha and Adam do not appear) and decides to have some fun when Larry drops in. At first the pill turns gray haired Larry into a redhead. He also acts the way he did when he was younger and thinks it is the same year when he was that age. At one point he thinks it is the early 1960s and says the Mets might win the World Series at the end of the decade. He turns into a teenager and finally a little boy, until Serena finally brings the antidote. This is the last time we see Serena.