XLR8

"I always preferred XLR8 over Fasttrack." - Ben Tennyson.

Ben as XLR8
XLR8 is a velociraptor like creature with a long tail and a pointed head. Ben's appearance as XLR8 looks almost exactly like his Ben 10,000 version.

Ken as XLR8
Ken as XLR8 looks very similar to how he appeared in the original series.

Credit
The picture in the infobox belongs to elmike9.