Frog Carrying Crown

The Crown Frog appears in "The Witch's Garden". Finn and Jake are following it because Finn wants to see it put on its crown. However, it walks into the witch's garden through a gate which Finn can't get past until being stretched over the gate by Jake. It is unknown what the frog's purpose is, but since it lives in the garden of the Witch it may know her, but it is never seen for the rest of the episode.

The same frog (or one that looks similar) makes an appearance in "Loyalty to the King" when Finn drops a monster head on the ground and a frog hops inside it.