What would Waluigi's special ability be in a 2D Mario platformer?

[OssieTheOstrich]

Swimming faster underwater perhaps?

List of projects I eventually plan to finish after the indefinite hiatus is over, assuming I don't abruptly cancel them:

Spoiler

Mario's Rather Unusual Trilogy (Mario's slightly unusual Boss Rush (Completed), Mario vs. Some Unusual Foes (In development), Mario's VERY Unusual Final Frontier (In development))
Sonic's Foray into Random/Unusual Zones (spin-off of Unusual Trilogy, in development)
Angry Birds Slingshot Frenzy (In development)
Super Mario Flashback: Really Good Edition (In development)
Super Hilda DX (In only conceptual phase)

Yes, I am aware that I have about 6 or so fangame projects currently in development at the same time. And yes, I am also aware that all of this is very ambitious.

+ List of projects I'm helping out with in some small capacity during my hiatus:

Spoiler

Super Mario Bros Dimensions 2 (as a spriter, only for Mario's sprites)
MFGG Community Fangame Project 3 (as a spriter)
WordGirl ReWired (as a artist)