Stybba was a pony that King Théoden of Rohan lent to Meriadoc Brandybuck after Aragorn, Legolas, and Gimli rode off with the Grey Company. Described as shaggy and grey, Stybba carried Merry through the mountain passes from the Hornburg east and south to Dunharrow and thence northward to Edoras. Though suitable for mountain riding, Stybba was too slow to accompany the mustered army of Rohan across the plains from Edoras, and Théoden ordered Stybba and Merry to stay at the Courts with Éowyn. Merry did secretly complete the journey with a Rider named Dernhelm (who was in fact Éowyn in disguise). Thus Stybba was left behind in Edoras and did not come to the Battle of Pelennor Fields.
 Portrayal in Adaptations
- Merry is indeed shown riding a small pony while traveling with the Rohirrim from Edoras to Dunharrow. Though this pony is not identified as Stybba, it is obviously a reference to Stybba.