The Forest, Mountain, and a Jester

The Forests and Mountains have always hated each other. The Forest tries to grow its roots across and over the Mountain while the Mountain tries to grow and uproot the Forest.
The Forest found a Jester roaming through her trees, she knew this Jester had many tricks and powers, she asked him to help her against the Mountain. She asked the Jester, "Please help me. Contain the Mountain in a prison so that he may never hurt me or my forests again" The Jester agreed with a smile, "But of course. In order for it to work, I will require a seed from your wisest tree. I will plant it atop of the Mountain so that you may overgrow him" The Forest agreed and gave him a seed from her oldest and tallest tree. The Jester made his way towards the Mountain to climb to the tallest peak and meet him.
The Mountain was aware of the Jester, his power, and his deal with the Forest. When the Jester reached the top of the Mountain to plant the seed, he pleaded to the Jester, "No, you must help me. The Forest would be rid of me had she her way" The Jester paused. He thought before he spoke, "I see, allow me access to your deepest cavern and I will make it so that you are unconquerable" The Mountain happily agreed and guided the Jester down his deepest trenches.
The Mountain brought the Jester all the way down to the core. With a devilish grin, the Jester took the seed and made it grow around the Mountain encapsulating him in an unbreakable prison. The Mountain shook and roared with anger, his ranges grew in number and size. The Forest could feel the Mountain trapped in her roots but unable to stop him, the anger furiously shaking her roots.
Both the Mountain and Forest asked the Jester why as he smiled and danced along his way.