I've seen my share of fancy sports cars making ridiculous flips in GTA V. But I've never seen anything like this.
The video above showcases a fantastic stunt jump performed by BlackSmoke Billy. Essentially, the semi grabs some air, the trailer unit detaches from the cargo and makes a front flip on its own, lands, and then has the cargo reattach on the ground as if its no big deal. I think the pedestrian in the video here sums it up pretty nicely: "OH SHIT!"
This isn't an isolated trick. BlackSmoke Billy seems fond of stunts with unusual cars -- here is a semi-truck front flip:
A dump truck corkscrew:
A semi truck corkscrew:
And the most badass way to attach to a trailer (on the ground):
God damn. Nice work, BlackSmoke Billy.