The Bolting Horse
Scholars have said that whoever sees themselves on a bolting horse, they may commit a sin or suffer a terror proportionate to the horse's difficulty. The horse in this case may refer to their passions that run wild with them. Riding a stubborn horse may indicate something more terrible and greater.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam
Note: These are traditional scholarly interpretations (ijtihad) drawn from a specific classical source — not a binding religious ruling, fortune-telling, or a prediction of the future.