10. That Time He Made Deadpool Immortal Out Of Spite
Unlike his MCU counterpart, comic Thanos loves Death. And not just inflicting it, Thanos is in love with the literal personification of Death. The issue is Death doesn’t love him back; she only has eyes for one Wade "merc with a mouth" Wilson, AKA Deadpool.
So like any good incel Thanos spends his time throwing temper tantrums and complaining Deadpool isn’t good enough for her (which in this case might actually be true). Not that it makes a difference though - Death is a grown cosmic entity and can make her own decisions. Thanos, however, isn't the most progressive when it comes to cosmic romance, and in the pages of Deadpool #64, finally decides to do something about his romantic rival, cursing Deadpool with immortality so he and Death can never be together.
So how would this look on screen? Well we already know Ryan Reynolds and Josh Brolin work well together, as demonstrated by their partnership in Deadpool 2, and a romantic comedy where Deadpool and Thanos compete for the affections of a literal skeleton is the movie we all need to combat Marvel fatigue.