Make Zelda's down taunt kill Giygas on Devil's Machine after using it 9 times.

Make Black Mage's Neutral Special stop everything in the stage including himself.

Add melee airdodge, but only for .
Everyone else get ultimate's air dodge.

Remove all characters but marth, then only add in the fire emblem characters from smash ultimate, then rename the game fire emblem flash.

Let Mickey Mouse, Scrooge McDuck, or Bugs Bunny join the battle! ...and there goes your childhood!

BTW, Jiminy Cricket is in the game as Sora's taunt!

replace every character with miis based on them.

's taunt is explosive and does about 950 damage, but doesn't make characters flinch.
's side special works like his final smash in smash bros ultimate, and can be used infinitely.
does 1000 damage when hitting with a home run bat, and all of his attacks spike in midair.
's arrow increases in size the more it is charged.
's punches do 1 damage, but his kick makes your opponent explode.
's side taunt can break shields and has serious knockback when first used.
can use shadow clone jutsu infinitely.
's side taunt is earrape.
says "D'oh!" everytime he gets hit and it gets louder each time.
pulls his nose so far it loops around the screen at hits him in the back of the head. it does damage on the way back.
's falcon punch is activated first frame and can be held down.
gets his own tier at the bottom like kirby did, called "not really mega man" or "MM tier" after being ultra nerfed.
's "you're too slow!" is like lip's stick except it can reach 999 damage in less than 5 seconds.
's standard taunt does 999 damage and stuns the player.
explodes randomly.
Goomba is a starter character that attacks by running into players, and can only be jumped on by Mario.
blaster can be charged, and when fully charged, comes out the size of the level.
the devil's machine increases x50 it's length.
Battlefield explodes randomly.
Final destination drops bombs sudden death style but increases frequency every second that passes.
can eat the stage.
's fart covers the entire stage in green gas and does massive damage to everybody.
's sword can actually cut people in half.
's dancing blade goes on forever.
rapidly shuffles through his palette swap.
Missingno. returns and actually crashes your computer.
can drop infinite bombs and they are all smart bombs.
Smart bombs increase in size forever until it covers the entire screen.
Fireworks spawn everytime a firework explodes
add a below minimum graphic setting
is invincible and explodes if interacted during his down taunt.
's tongue extends farther than the devil's machine.
's rest is effective regardless of where your opponent is.
fireballs from the fire flower bounce forever.
expands every time he taunts.
explodes forever when sheik until turning back to zelda.
can through bombs forever.
's standard taunt is uncensored and causes players to get a nosebleed and go flying anime style.
waluigi.
's side special tracks the player and pins them down upon impact. If in the air it will spike the player down and pin them if they touch the ground.
's electric attacks don't do electric damage but his non electric attacks do.
's PK fire is rapid fire. Pun intended.
gets bigger in certain places when getting the super mushroom.
Attacks do 200 damage if you are tiny. You also become microscopic when coming in contact with poison mushroom.
if you choose invisible smash, you aren't invisible; you simply don't exist. for the entire battle. if a stock match, text appears saying "you are stupid." and the game crashes and can't be booted up for 72 hours.
Special Smashes are legal.
sometimes playable characters come out of assist trophies as level 9 CPU. They are invincible and always have their final smash.
pokemon come out of assist trophies, and every pokeball is explosive unless it's missingno.


And finally,

shields can be held up forever and every character explodes after 5 minutes in battle.



Edit:
Characters

Add Mickey Mouse. Have the rest of the cast be echo fighters of existing characters.
Add Randy Cunningham: 9th grade ninja as a playable character.
Make Frankenstein (the scientist) a playable character and make Frankenstein an assist trophy.
Add doctor luigi instead of doctor mario, then nerf him to the point where he does 0 damage.
Ayano (Yandere-Chan) as an echo fighter for marth.

Add Giorno Giovanna and make him a clone of Isaac.

Make Tails' down taunt let you control robotic characters ( , ) while you have the taunt button held.

Make Link shoot a sword beam when he uses any sword attack, but only at 0% damage.
The beam's shape and size depends if it's a sword slash or stab, its swing power etc...

Make have start-up lag when jumping like in v0.8.



Edit: and make it as long as Ganondorf's Warlock Punch AND 's Falcon Punch combined.



ANOTHER EDIT: and give his old up special. And make sure it's was broken like in v0.8. And make freefall cancelling an actual technique.

Increase hitstun by 400%

Give Zelda Witch Time.

His dab should be an instant kill
He should have infinite jumps
Kamehameha should be instant and his down b phase permanent
His up b should be a nuclear bomb
He should be able to call Epona on the battlefield
He should be just like in brawl
He shounldn't be able to move. As he's a sandbag, it does make sense
When eaten, an ennemy should become a following egg, just like in Yoshi's Island

Make all the characters have their viability depend on how powerful they are in the media they are represented in.