When the gang meets Olaf, Anna is the first to introduce herself. Olaf then leans into Anna, asking who "the funky-looking donkey over there" is. Thinking he is confusing Sven, who is a reindeer, for a donkey, Anna tells him that it's Sven. But Olaf responds, "Uh huh, and who's the reindeer?" From then on, Olaf thinks that Kristoff and Sven both have the name "Sven," which, as he points out, "makes things easier" for him.
It's laughable when it occurs, but not necessarily something the viewer thinks will come back up. But, in a turn both clever and sensible (seeing as Olaf is never corrected), Olaf continues to refer to Kristoff as Sven. In one subtly hilarious moment, Olaf calls out to Kristoff, saying, "Hey, Sven!" in an effort to get his attention. The payoff is killer: Kristoff responds to the mistaken name without blinking an eye.
This joke continues on for quite some time, until finally, Kristoff takes them to meet his troll friends. One of them exclaims, "Kristoff's home!" Olaf repeats this, mirroring their enthusiasm, then leans into one of the trolls and asks, "Wait ... Kristoff?"
