I saw a good suggestion earlier, and I'm going to expand on it a bit.
Deadpool "One Shot" where he kills the Fox Marvel universe, much like the X:O scene from Deadpool 2. Since he is self-aware of the merger happening, and recognized a need to reboot, he goes through all the terrible Fox Marvel movies (Old F4, New F4, Old X-Men, New X-Men) and kills off each and every one of them, so that he (and those from the Deadpool franchise) are the last ones standing, therefore increasing his chance of surviving, since there is no longer a need to do a clean sweep.
Can even throw in a quip about killing off the cast of Phoenix and New Mutants before they could finish the films "check Netflix, they may reincarnate there". and then even kill off those in the writing room who were working on scripts for that Dr. Doom movie, and any other potential FoX-Men films (Kinberg, Singer, etc etc), and then he can burst onto the set of Channing Tatum's next movie and kill him too, just for good measure, and to ensure that Gambit movie can now never be made.
I think it would make for a great and hilarious short to be aired right after Avengers 4.
it could then end with the title card of Deadpool will return..... in the MCU!?
this is assuming of course that they get everything cleared before end of the year, so they have time to actually make this.
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