Wow, Snake's up-smash is a very interesting move. For starters, it's kinda difficult to tell when it's been reflected; Ness' bat gives no visual confirmation that it's reflected the mortar, except that its horizontal momentum gets reversed
if it had any.
But more importantly, the Mortar is the first evidence I've seen that the "elemental type" of an attack can have an influence on a priority mechanic. (Though I bet the Olimar and Pokemon Trainer ppl have a few things to teach me on this matter
) scotu is right, in that some aerials can "beat it" (the mortar explodes, causing no damage to anyone), and some can pass right through it. In fact, there are ground attacks that can go right through it too. And
as far as I can tell it has to do with the
type of attack.
The Subspace Emissary's sticker mode demonstrates that every attack in the game has at least one of at least the following types: Arm, Leg, Weapon, Head, Body, Spin, Throwing, Tail, Magic, PK, Bite, Energy, Explosive, Slash, Electric, Flame, Aura, Freezing, Water, Pikmin, Grass, Darkness. I'm not sure about these: Direct Specials, Indirect Specials, and Battering. There might be others, those are just the ones I got from my incomplete sticker collection :-)
I don't know if a hitbox can have more than one type. If there's a better compendium of this stuff and its effects somewhere, please let me know.
In my experiments, Slash attacks pass right through Snake's Mortar. I'm talking about the rising and falling of the mortar, not the explosion it causes when it lands; that seems to be different. For example, Lucario's Aura Spheres will pass right through the mortar during its rise and fall, but they will clash against the explosion it makes when it hits the ground.
Anyway, back to Slash attacks..... consider Toon Link. His Dair, Uair, and Nair will all destroy the mortar, if spaced properly. But Toon Link's Fair and Bair will pass right through the mortar, and neither will be interrupted, leaving Toon Link vulnerable to the mortar. Note that the Dair and Uair both stick out the sword and keep it in a solid position, whereas the Fair and Bair do large swipes with the sword: Slashes. His Nair looks like a slash but I think it might have both a slash hitbox and a weapon hitbox, for some reason.
This trend about Slashes seems consistent across characters, though. MetaKnight, for example, cannot use any of his aerials to kill the mortar. This might be a very small part of why Snake makes a good counterpick for MK
It also looks quite strange that Link's Nair "kick" (more like sticking-his-leg out) kills the mortar whereas his huge sword-swiping Fair misses it entirely.
As another example, Ness' Dair, Bair, and Nair all kill the mortar, but his Fair cannot. I couldn't get his Uair to hit the darn thing without it hitting Ness' hurtbox first, so I can't comment on that. Also of note: Ness' Yo-yo will
not clash with the mortar! Even though his Yo-Yo seems to clash with a lot of regular
aerials, which is unusual on its own. Although I should hold my tongue, since many of my previous aerial-priority statements may be invalidated if the effect of elemental types is strong. I suspect that the elemental type system will be at work quite often with Specials, but this is all speculation.
It's possible I'm just crazy, and I've misjudged what's going on here! Or that this is a well-known phenomenon already? Please let me know.
Edit:
About the u-smash thing, it only happened to me once. Ness' nair clanked with the yo yo as it was going up.
Don't worry, I've been able to reproduce this lots of times. All aerials I tested would cause the Yo-yo to clash; although I might have just been testing with one particular "type" of aerial that would do this, whereas other types might not? :S
