Beholder Panoquai was a Ophidian tasked with the narration of what happened inside Ophidius.
He followed the Doctor and Izzy, thanks to the isotemporal circuitry in his flying chair, that allowed him to exist a nanosecond into the future and being effectively invisible. When he got close to the Doctor to kill him, the Time Lord senses allerted him of the disturbed time field, allowing him to knock out the Ophidian.
Izzy and Destrii guarded him while he was unconscious, while the Doctor went for a test-flight with his chair. When he woke up, he was forced to guide the two girls to the eye-like structure where the Doctor supposedly was. There, Destrii shot him, as he was a witness of the body-swap done by her with Izzy's body. He freed Izzy, now in Destrii's body, from the chair she was strapped in, shortly before the Reciprocator's explosion killed him for good. (COMIC: Ophidius)