ZIP-0 was a robot created by the Spooky Aliens. It was designed to accurately resemble Zippy so that it could lure Mulder into a trap. It did this as the Spooky Aliens needed to extract more emotions from Zippy so that they could create the Abomination.
The Somewhat Pointless Adventures of Zippy Edit
The ZIP-0 robot was first seen when it infiltrated Mulder and Zippy's house. It successfully managed to blend in and managed to convince Mulder that it was the real Zippy. The two went out on a date to a festival, where Mulder was converted into a strange being the robot named 'Neo Mulder'. The real Zippy confronted the robot and got into a fight with it. He eventually managed to win and he confessed his love to Mulder. The dying robot picked up on this last emotion and sent it to the Spooky Aliens, allowing them to finally finish the Abomination.