Sonic was running through the Warp Zone when he found a Chaos Gate that lead to Earth. The Blue Blur saw the elder Saiyan prince & was glad to see his old friend. The elder Mobian prince decided to jump in & pay a visit.
Sonic: Vegeta! Long time, no see! I haven't seen ya since we took down Broly as Gogeta & Shadic!
OOC: It would make more sense if you saw the third video in my headcanons! Nice profile by the way!