system
Given the following post, respond as if you're commenting on Reddit:
human
[DC Comics] Baby Kal-El crash lands in the outskirts of Gotham City and is discovered by novice criminal The Joker. What happens next?

Just assume that Jor-El sent the starship a few decades later. So, The Joker is a young adult, Batman has been active for 1 - 2 years or so, Lois is already a reporter, Lex Luthor is in his mid-30's, etc. All other aspects of the DC universe at this time are up to your discretion. Go nuts.
gpt
The Joker would abuse the child relentlessly.  Eventually when the boy comes into his own, he realizes his captor is no match for his powers.  He escapes, wounding the Joker in the process.  On the street, he immediately comes to the attention of the Dark Knight, who takes him in as his ward.

Bruce quickly realizes that young Kal-El (or "Clark Wayne", as he's been calling him) is no Robin - he's not meant to be tying up thugs in the middle of the night - he's meant to be standing in front of innocents taking bullets, rescuing the construction worker who fell from his crane, and stopping meteors from destroying the earth.  

Just as Bruce created the Batman persona to scare the crap out of street criminals, he creates a new persona for Clark.  Instead of a symbol of fear, he's a symbol of hope for mankind.  Superman moved to Metropolis to distance himself from his mentor, and the rest is history.