The Fresh Prince is now entering the "I've made A LOT of money for you motherfuckers so now I get to do whatever the FUCK I want!" phase of his career (his next big project: a father/son scifi action/epic with Jayden written and directed by M. Night Shyamalan); and if you need further proof of this The Wrap reports that he's gotten a greenlight to produce, star in and possibly even direct "The Legend of Cain" - which apparently retells the Old Testament tale of Cain and Able with "a vampire twist."
Okay, so... this sounds batshit insane as a film project ("what if Bible Character X was a VAMPIRE!!??" is almost a parody of controversy-bait movie pitches) but the disillusioned Catholic School student and Altar Boy in me can actually see how this might be an interesting premise.
If you're not up on your Ancient Jewish religious/folk traditions (though this particular story is also held as relevant/important by Christianity, Islam, Mormonism and other Abrahamic-offshoots), Cain and Abel are supposed to have been two brothers (twins in some tellings) sired by Adam and Eve at some point after they were expelled from the Garden of Eden. The specific circumstances vary from source to source, but the main point of their story is that Cain kills Abel in a jealous rage when God rejects Cain's burnt-offering of fruit but accepts Abel's sacrificial offering of a lamb - thus turning his brother into the First Martyr and himself (Cain) into the first human being to commit the sin of murder... and the subsequently the first human to be Cursed by God as punishment.
Here's where this gets interesting, to me: Given that this is an Antediluvian Biblical account (read: takes place prior to The Flood and Noah's Ark) the story of what happens to Cain AFTER the murder vary wildly from tradition to tradition, to the extent that even many "traditional" sects see it more as a symbolic account than a literal one. In any case, Cain's punishment takes different forms in every telling. Chiefly, he's supernaturally blocked from ever being able to farm or cultivate the earth again (having spilled his brother's blood there) and is commanded to wander the world ever-after as a scavenger. Moreover, he's branded (sometimes literally) with "The Mark of Cain" which has a troubling history as certain faiths decided that black (as in African) skin was evidence of said Mark and used it as pretense for racial segregation (most mainstream Christian faiths, however, held that whatever descendants Cain DID have were among those killed during The Flood.)
BUT! Some other, more mystical Judeo/Christian/Islamic traditions hold that Cain's "wander forever" curse meant forever as in immortality. Considering that, and considering how prominent the imagery of blood (the Bible describes the poisoning of Cain's land as the result of the earth having been "made to drink his brother's blood) is in the story it wouldn't be that far of a leap for this film to go with "The Curse and Mark of Cain was actually that he became the first Vampire" as it's big-idea twist.
Amusingly, if Smith does decide to play Cain himself and casts the remainder of the characters accordingly (how great would it be if Alfonso Ribeiro played Abel??), making it into a vampire movie is just about the ONLY thing that could distract from the innevitable firestorm of "I'm not a racist BUUUUUUUT...." protests at the idea of Biblical characters being portrayed by Black actors.