The "adult" movie Kevin watches in Home Alone. Apparently the main dude who was supposed to be in those didn't show up so they just had some janitor or tech fill in and he went full ham on that shit and made it something to remember.
There's also the McBane movie in The Simpsons that shows up in multiple episodes and if you connected them all together they actually make a coherent story line (it's just riffing off Lethal Weapon anyway).