DACUS is Dash Attack Canceled Up Smash. Snake's Mortar Slide is a DACUS.
Anyway, I remember you saying something, Magnumblade, about using our friendly matches in the SIMPLE Luigi Ladder as a chance of practicing your Sliding fSmash. I don't remember you using it on me and I completely forgot about it. To practice it myself right now I had to change my controls (Wiimote + Nunchuck's Grab is A+B simultaneously which is hard to pull-off even by itself) so that now the C button is grab. My D-Pad acts like the C-Stick on the GC Controller, so all I do now is Walk -> D-Pad -> C button to pull it off.
I think you're onto something Magnumblade. The next step is to practice it till it becomes muscle memory. Then after that, the next step would be to spam the hell out of it until we find out when (if ever) it's useful in combat.
Like I said, I've changed my controls to be able to pull this off. I plan to help you find the practicality of this Sliding fSmash, if there is any, so I'll be spamming it in friendlies when I get good at doing it consistently. It'll be especially hard for me since I rarely walk; but that's something I've been meaning to improve on anyway.
---------------------------------------------------------------------------------------------------------------
EDIT: This is harder for me to do consistantly than I expected. My left index finger naturally rests on the Z button, so I either have to pre-plan and prepare for a Sliding fSmash by putting my finger on the C button first, or I have to put both my index and middle finger on the C and Z button respectively to be ready at a moment's notice. I've decided to try t get used to using two fingers, and teaching my middle finger what the index used to do (Shields).
Anyway, still within the EDIT, I've realized that while Slide fSmashing, you get time to decide if you'll tilt it up or not. If you suspect you won't come within reach of the fSmash, you would keep the fSmash untilted to give you as much reach as you can get.
But what's discouraging (MASSIVELY discouraging) is the fact that you have to first get up to speed by walking for a distance, albeit short. It can't be done from a stand-still like the Hyphen Smash. So you have to either pre-plan the Sliding fSmash, or already be in a brisk walk toward the opponent. Neither of those sound good to me. Pre-planning the next move is generally bad in Smash Bros. and Luigi has better things to do than to walk toward an opponent.
With that said, I still think this should be explored, and I still plan to spam this in friendlies to see what it can do.