Damsel in Distress: The Russian ballerina, Irish Riverdancer and later Alex get kidnapped by the show host and tied up so their feet can be stolen and tested. Intense.
Freudian Slip: After Bethany introduces herself and reveals that she's their new roommate:
Clover: Roomie?! Ah, it must be a mistake! Our closets—our, I mean, our penthouse is crammed to capacity!
Genki Girl: Bethany makes Alex look chill by comparison.
Literal Metaphor: The Villain of the Week's motivation turns out to be that he has two left feet...and is looking for the perfect right foot to steal.
My Nayme Is: Bethany's name is actually spelled with "two Hs, two Ns, and two... [strange, long E sound]". What exactly this works out to is unclear, to the point of briefly causing an edit war on the Totally Spies! wiki.
