Mythosaur

"You are a Mandalorian. Your ancestors rode the great mythosaur."

- Kuiil scolds the Mandalorian

Mythosaurs were a type of creature that was once ridden by members of Mandalorian society. In around 9 ABY, the Ugnaught Kuiil was training a Mandalorian bounty hunter to ride blurrgs on the planet Arvala-7 and scolded him when he tried to give up, reminding him of the fact that his ancestors would have ridden mythosaurs.

Behind the scenes
Mythosaurs were first mentioned in the current Star Wars canon in Chapter 1 of The Mandalorian, a television show that began airing in 2019. The species originates in the Star Wars Legends continuity, where they were created for the in 1982 comic book Star Wars 69: Death in the City of Bone, which was written by David Michelinie.