 Ted told Carl the meaning of the word "karaoke" and that he wanted to go see some penguins at the zoo, then suddenly called someone (presumably Robin) and told her come over and do something "crazy".Based on this information, Marshall, Lily, and Barney believe that the mysterious girl in Ted's bed is actually Robin, but as Ted goes to wake her up, Robin calls and tells him she is coming over to discuss the previous night.The girl in bed, Trudy (Danica McKellar), wakes up, and explains her side of the story