Telchak, also known as Chak, is a Goa'uld.
He found a device used by the Ancients to heal. The device was so powerful, however, that it was harmful to Humans. Telchak was able to perfect the device and turn it into the first sarcophagus, eliminating the physically damaging side effects, without removing the negative effects it held on the users brain chemistry. Anubis soon went to war with Telchak over the device. Anubis was victorious, but Telchak managed to hide the original device on Earth. His fate remains unknown. (SG1: "Evolution, Part 1", "Evolution, Part 2")