"See the Bear of fearsome size! All the worlds within his eyes"
- An old saying

Shardik is one of the twelve guardians of Beams that hold up the Dark Tower. It is a cyborg bear that stands over forty feet tall and has a contraption affixed to its head resembling a satellite dish (known as a thinking cap by Roland). Shardik was built by North Central Positronics, the mysterious company which was a part of The Imperium thousands of years prior to the events of The Dark Tower Series. Shardik was known as Mir by tribal groups who once lived in the woods of his domain, which in their language means, the world beneath the world. Shardik's functional longevity is most likely due its internal nuclear power source.

Stephen King - The Dark Tower series