When Did Mac Gargan Become Venom?

[key2win]

I havent read or caught up with comics in a long time. I recently found out that Mac Gargan is now Venom. So he is no longer the Scorpion. What happened to Eddie Brock? How did Mac Gargan change from Scorpion to Venom?

[toylad]

Cliff note version-

Eddie Brock developed cancer and auctioned the symbiote off to the highest bidder,the symbiote thought it's new host to be weak and left him and attached with Gargan when he was on a mission for Norman Osborn,later it tried to rebond with Brock who because of cancer treatment is now caustic to the symbiote resulting in a white substance to ooze out of Brock covering his body and changing him into Anti-Venom.

[key2win]

Thanks for the info.