The Ukrainian Ironbelly is a species of dragon native to Ukraine from the Harry Potter franchise. It is said to be the largest dragon species in the world.
Ironbellies have been subject to constant observation by the Ukrainian wizarding authorities, ever since a particular Ironbelly carried off a sailing ship from the Black Sea in 1799. Thankfully, the boat was empty at the time. In 1926, Newt Scamander mentioned to Jacob Kowalski that he had previously worked with Ukrainian Ironbellies during the First World War.
Gringotts Wizarding Bank owned a Ukrainian Ironbelly that guarded some of the oldest and deepest vaults, including the Lestrange Vault. This dragon could be subdued by using clankers, a rattling mechanic that the dragon had been taught to associate with pain. It broke free in 1998, with the help of Harry Potter, Ron Weasley, and Hermione Granger during their break-in and escape from Gringotts. The dragon carried the trio to a far-off lake where they jumped off and the dragon continued to fly away.