Avatar- Otter penguin

In Avatar The Last Airbender, first seen in Episode 1, The boy in the Iceberg, Aang says to Katara, "Will you go penguin sledding with me?"

The two do go sledding, on cute animals called Otter- penguins.

Otter Penguins are mainly found in the Southern Water Tribe.

After being released from the iceberg, Aang's first request was to go penguin sledding with Katara, which she confusedly accepted. Later, upon seeing an otter penguin, a fascinated Aang immediately chased after it. Katara found him attempting to catch the animals, with little success. With Katara's help, he used fish to bait the penguins and, after being nearly trampled by the hungry creatures, managed to catch one on which he could go sledding. Katara caught a penguin for herself and joined Aang. As the two reached the end of the slope, their otter penguins tottered back up to the rest of the colony.

Aang later rode an otter penguin while returning to the Southern Water Tribe village after being banished, in order to save the residents from Zuko.