'It's just Charizard.', you say to yourself... Just be patient, and all will be revealed.
Behold! The number zero!
Deal some damage, and the number increases!
Que Pikachu punching bag montage.
This number will increase based on the amount of direct damage (I.E. Non-projectile damage) you deal, with its cap being 150 damage dealt during a single stock.
And it will reset if you get KO'd, so be careful.
To initiate this number check, activate your shield, and press B at anytime while shielded (basically L/R + B).
So what happens when this number reaches 150? An aesthetic indicator will activate, which will allow you to...
Press A during Neutral Special's startup (basically A + B)...
To turn into an egg...
And presto! Mega Evolution has been achieved! You can pick and choose which of the two Mega forms to use by holding A for Mega X or B for Mega Y. Though if a button isn't held, it will instead randomize an option for you. Your Mega Evolution will also go away if you are KO'd, requiring you to deal 150 damage again to get it back.
So now let's go over what Mega Evolution has to offer, starting with Mega X. When compared to its default counterpart, Mega X sports higher falling speed (10% increase), higher gravity (10% increase), and higher ground jumps (10% increase) in addition to all direct (non-projectile) attacks receiving a 1.15* damage bonus. All fire attacks have also been changed to deal aura damage alongside all red effects being changed to blue.
In addition to the changes I listed, Neutral Special changes from Flamethrower to Thunder Punch (taken from P+). A horizontal rush on the ground and a dive punch in the air.
Side Special also changes from Heat Wave to Flare Blitz. A powerful move with recoil damage. While it's mostly a port of its Smash 4/Ultimate counterpart, this move has one key difference, being that the move ends in Fall rather than Tumble when ending in the air or making contact with an enemy/wall.
Now let's head on over to Mega Y. When compared to its default counterpart, Mega Y sports lower falling speed (10% decrease), lower gravity (10% decrease), lower ground jumps (10% decrease), higher air speed (10% increase), higher air mobility (10% increase), and one additional air jump in addition to all direct (non-projectile) attacks receiving a 1.1* damage bonus. All fire-based attacks also have an increased base damage (before the 1.1* multiplier, knockback compensated).
I bet you're wondering what that lingering flame in its mouth is for? Well that's because Neutral Special changes to Fire Blast (this is the only Special which changes when using the Mega Y form), a powerful piercing projectile which initiates a 10 cooldown when used (the flame will re-ignite once the cooldown time passes, but it will not decrease when using Neutral Special). Though when on cooldown, Neutral Special changes to Smokescreen, a powerful gust of smoke which blows back foes and can potentially gimp a recovery with proper prediction.
For some added flair, if you win a match when Mega Evolved, your chosen Mega form will show up on the Results Screen, but will revert to the default form if you lost or quit the match.
For those who remember, yes, this is the fabled revamp to Solo Charizard which was thought to have been canceled. This revamp aims to be smaller in scope and more balanced than its original counterpart (though I'm aware some aspects of this mod can and will be considered too strong and/or unfair depending on one's perspective), but is overall a more casual-oriented mod, as I'm well aware how much of a huge buff adding such a mechanic would be, especially on a powerful mid-tier like Charizard.
In terms of release, I want to wait until I finish the Mega Evolution GFX before I release, as what I have now lacks a few iconic effects (such as the rainbow ribbon). For now, this revamped mod will be for Project M only, but might have P+, Brawl, and Brawl Minus versions if there's enough demand.