The Cosmic Man

Susan Ivanova discovers a derelict spaceship in hyperspace. They tow it back to Babylon 5, then strange things start happening. People are being telepathically taken over by aliens from another (third)space.

An alien similar to Ra appears out of the Stargate, killing five soldiers and kidnapping another, a year after the original Stargate mission. A new team is assembled, including some old members, and they go in search of the missing soldier in order to find out how Ra could still be alive. Meanwhile, the alien Goa'uld kidnap Sha're and Skaara, implanting them with symbiotes and making them Goa'uld hosts.

The explorer craft USS Palomino is returning to Earth after a fruitless 18-month search for extra-terrestrial life when the crew comes upon a supposedly lost ship, the USS Cygnus, hovering near a black hole. The ship is controlled by Dr. Hans Reinhardt and his monstrous robot companion, but the initial wonderment and awe the Palomino crew feel for the ship and its resistance to the power of the black hole turn to horror as they uncover Reinhardt's plans.

Aliens have landed and are hiding on Earth, but need Earth’s scientists to help them fight an inter-planetary war.