Invasion storyline started about the same time as his Stalking storyline. They should have made him a major palyer in the Invasion from the begining. It would have given it more credibility, especially since the WCW invaders were lacking star-power so much that they alligned with ECW. While I liked DDP in WCW, like most things in WCW at the time, he was not on par with what the WWF was doing..i.e. Austin, Rock, Angle
When WCW was purchased by WWF owner Vince McMahon in 2001, Page was one of the few major WCW stars to sign with McMahon. He debuted in the WWE on the June 18th, 2001 edition of RAW when he unveiled himself as the stalker of The Undertaker's wife, Sara. Page did it to make an impact and wanted to take on the biggest dog in the yard, but he then became obsessed with Sara. Page soon joined the Alliance during the WCW Invasion.
The feud with the Undertaker went on for the best part of Three Months and ended when Undertaker and Kane defeated Page and Kanyon at WWF Summerslam 2001 on August 19, 2001 in a Steel cage match for the WWF tag team championship, where Page got injured which kept him out of action until late October, 2001.
At age 46, he had nagging injuries, including a neck injury he suffered in a match with Bob Holly on the April 18th, 2002 episode of SmackDown, so his WWE contract was allowed to expire. WWE wanted him to do color commentary, but Page opted to take a break from wrestling, citing that he was "burned out."