Son of the White Mare (1981)
A horse goddess gives birth to three powerful brothers who set out into the Underworld to save three princesses from three evil dragons and reclaim their ancestors' lost kingdom. princess, sibling relationship, fairy tale, mythology, castle, surrealism, rope, dragon, adult animation, folklore, superhuman strength, psychedelic, abstract, griffin, porridge, hollow tree, cartoon horse, brothers, underworld, cartoon snake