If your horse isn’t able to move the rock during the "Crystal Caverns: Glamour Gulch" quest, there are a few common workarounds that may help:

• Ensure your horse is a generic horse of at least Level 2. Pushable crates and rocks can only be moved by a generic horse once it reaches this level.
• If you are stuck in the green area near the bridge, please make sure the bridge has been lowered first. The rock cannot be pushed until this step is completed.
• Check for any dead wishblossoms blocking the crate or rock. If present, remove them before attempting to push the object again.