Soon after Grandpa Max reveals his past Plumber activities to Ben and Gwen, his old partner Phil turns up. Phil didn't retire at the previous fall of Vilgax as Max did. He's still going about rounding up aliens that occasionally pop up. Upon discovering Ben and the Omnitrix, he sees a renewed partnership with the Tennysons forming. Ben's all for it, but Grandpa Max is leery, and the Omnitrix is back to delivering aliens contrary to what Ben calls up. Written by
Did You Know?
In the credits, both Paul Eiding and Robert Patrick appear to be credited for playing two character apiece (Grandpa Max & Seasoned Pro, and Phil & Rookie, respectively). They're actually each playing one character at two different time periods about thirty years apart. "Seasoned Pro" and "Rookie" should've been established in the script rather than through the credits. See more
And don't worry. I'll be sure to tell Ben how your last words to me were how you wanted him to follow in your footsteps as my partner.