Toadpoli

Toadpolis are enemies appearing in Twilight Princess, Link's Crossbow Training and Skyward Sword.

Characteristics
They appear as frogs but act very similarly to Octoroks seen in previous 3D Zelda games.

In Twilight Princess, they appear as armored, two-legged frogs who have retained their caudal fins. A universal trait of all Toadpolis is that they spit balls at Link, which he must deflect. If the young hero comes too close to them, they will dive back under whatever they're swimming in.

Toadpolis in Skyward Sword have eye stalks compared to their close-set-eyed Twilight Princess counterparts.

Variations
There are several variations of Toadpolis:

Water Toadpoli
In Twilight Princess, Water Toadpolis can be found in swimming in water in the Goron Mines and behind the Howling Stone in Lake Hylia. They spit rocks at the young hero that can be deflected with a shield. In Link's Crossbow Training, Water Toadpolis appear in the Rapids Ride level.

Fire Toadpoli
In Twilight Princess, Fire Toadpolis can be found early on in the Goron Mines, swimming in lava. They spit molten rock at Link that can burn his Ordon Shield or Wooden Shield. The molten balls in can be sliced with the sword and be deflected back at the Fire Toadpoli, killing it.

In Skyward Sword, they spit fire balls that can be sliced, rendering them ineffective. They can be found in the Earth Temple and can be rolled over with a stone ball inside the temple.

Electric Toadpoli
Electric Toadpolis appear in the Lanayru Desert region in Skyward Sword. They swim in sand and shoot electrified balls at the young hero. They can be destroyed with Bombs.

Trivia

 * Many believed that Toadpolis were actually Octoroks in Twilight Princess.
 * Toadpolis also bear an appearance and similar attacks as Zoras in the original The Legend of Zelda, and Link's Awakening. They also share some physical similarities to the Deku Toad.
 * Both the name and anatomy of Toadpolis seem to imply they're still in a stage of metamorphosis, which may explain their physical similarities with the Deku Toad.