Forget Ben Stiller or Andy Warhol ( yes, seriously ) ... the greatest WWE celebrity cameo EVER was executed (painfully) by Jon Stewart ... so says WWE legend Scott Hall .

Stewart was famously SLAMMED to the mat by John Cena during "Monday Night Raw" back in August -- earning him TONS of respect from the wrestling faithful.

And when we saw Hall leaving the Opie and Jimmy show in NYC ... along with Diamond Dallas Page and Jake 'The Snake' Roberts ... they all seemed to agree the former 'Daily Show' host became a WWE legend himself that day.