Pikachu >> Ness to Pikachu > Ness
Pikachu > Ness. This isn't as bad a matchup as the luigi match below. Ness at least has the priority to keep up with pikachu. Down air combos work well vs Pikachu. Pikachu can gimp ness so easily that it is still a + matchup but Ness's DJC prevent the >> matchup.
Pikachu > Luigi to Pikachu >> Luigi
Pikachu >> Luigi....Luigi can't gimp Pikachu well and Pikachu 's n-air, back air, and up air get luigi off the stage and edeguard way too easily. It comes down to Pikachu's incredible priority and approach.
Debating:
Luigi > Jigglypuff to Luigi >> Jigglypuff
Luigi >> Jigglypuff Combine the fact that Luigi up b kills....I think at 30, and that Luigi is so floaty that Jigglypuff has problems comboing.
Yoshi = Samus to Yoshi > Samus
Yoshi > Samus. Yoshi back air goes through virtually all of samus's moves. This is one of the few matchups that Yoshi is able to Up tilt to down air combo and not be punished. Also, Yoshi's N-air combos samus well at low percentages and Yoshi's DJCC can get Yoshi out of the few combos that Samus has.
Luigi = Ness
Luigi = ness. Its priority vs the up b. if Luigi had a better Shorthop and higher priority, it would be a >Luigi matchup (like the + Mario matchup).
Jigglypuff ? Yoshi
Jigglypuff = Yoshi. Its combos vs combos. Yoshi can DJCC out of many of jigglypuff's more simple rest combos. Yoshi Egg camping helps as well and Yoshi's n-air and back air out prioritize most of Jigglypuff's moves. Yoshi just needs to space to not be hit by that many throws, especially at lower percentages.
I agree with Yoshi > Samus, Jiggly = Yoshi
but some of the Yoshi reasons are weird to me
Samus is one of the few characters that Yoshi can't get out of Samus's combos 90% of the time. Samus's main staple combo, Down-air to anything (usually back-air) is pretty much impossible to double jump out of unless your opponent is slow or down-aired kind of high before getting charge shot (if this happens, Yoshi will most likely die anyways after eating the shot while double jumping).
Yoshi does combo the crap out of Samus, and has decent edge gimps that aren't hard to play off, not hard to shield pressure/ shield break Samus either, I really believe it's Yoshi > Samus but Samus can win if she plays extremely CAMPY/smart/mindgame style, pretty much the way Samus wins all her matchups
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In the end, I don't see any glaring flaws in this chart anymore, like I said before, some of these matchups are different or even indeterminable at extreme playing levels, but this is a good enough chart for now I think with some minor tweaks