Well, based on the close dittos Reducas did with my 11 year old.... "friend" I'd say Missile would be the logical choice. Possibly a perfectly spaced D Taunt. Basically, if you want to see the same success as Reducas, you need to:
1) Purposely lag your internet and refuse to play offline
2) John about "spam"
3) Use Mario's "baseball slide" more than any other move
I think you guys are being a bit too harsh on Reducas. Luigi and Mario are clearly extremely similar. Luigi's fall speed, traction, hitboxes, kill power, playstyle, and specials are nearly identical. Not to mention all the blatant similarities between "girl punches" and "baseball slide." Mario's Baseball Slide is the best move in the game by far. Less punishable than MK's D smash AND it can be used while running. Not to mention you can buffer a contious DA chain and it looks sexy. It may also cause your opponent to fall victim to one of your taunts.
In short, Reducas is the best at this game. What he lacks in intelligence and maturity he more than makes up for in creativity, trash talking, and johning. While all of you may believe he is a scrub, it is YOU who should stop talking and just listen.
Reducas, would you consider participating in a talk, assuming you have a mic, with some of the other top Marios weekly? Obviously no other Mario can compare to you and their scrubbish opinions may make this difficult, but I think it would help many Mario players to get better.