Black Knight
From The Stargate Omnipedia
Guardian of Merlin's library on the planet of Camelot, where his research on an anti-Ori weapon was kept. Instead of battling those who trespass within the library, the Black Knight emerges to the villagers to incite terror and discourage re-admittance.
The non-sentient technology is governed by an Ancient control pedestal. Once the correct combination has been entered on the pedestal the control crystals can be accessible, which can terminate the knight.
KEY EPISODE
Camelot - After the Black Knight has already killed one villager, Mitchell fights it to keep it occupied while Dr. Jackson attempts to deactivate the program.