Wood frog

A palm-sized, brown colored amphibian that lives in a swamp. During the winter, the frog hibernates by freezing and sitting at the bottom of the river bed. When frozen, the frog skin secretes a substance that has medicinal purposes, but when it thaws out it's just a normal frog again.

History
In "The Blue Spirit", Katara and Sokka fall ill, so Aang goes to The Herbalist and asks for help. The Herbalist tells Aang to seek out the Wood Frog. Aang finds Wood Frogs, and placed them into Sokka's and Katara's mouths and tells them to suck on them until the illness wares off. Sokka claims the substance is "tasty" but he (and Katara) spit the Wood Frogs out when they thaw out and start to wriggle. Sokka and Katara then start to cough and gag. Sokka claims to have a wart on his uvula (or 'throat-hole-flap') since then.

Connection
The Wood Frog is based on the real world Wood Frog, that can actually survive being frozen solid.

Trivia
The wood frog is one of very few nonchimerical (unhybridized) animals seen in the world of Avatar. Another example is Miyuki (who appeared in the same episoode) and another is Bosco, the Earth King's bear, as well as Hawky, Sokka's pet hawk, and the other Messenger Hawks.

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