To "Pull an Ariel" is when you point to a common known thing and ask "What's that word again?" the same way Ariel, The Little Mermaid asked in the song "Part of your world."
"Strollilng along down a
(What's that word again?)
Lindsay: (pointing to a picture in an Italian resturant) "What's that called agian?"
Lisa: "The Colosseum? Way to Pull an Ariel"