Alright here we go. We're gonna' start discussing match ups for Reptile, starting with Scorpion and working our way down the line, so, here's Scorpion's start.
I feel personally that Scorpion is an even match up, maybe a bit in our favor, like a 55:45. The tools Scorpion has on us that we actually need to watch out for is Spear, Hellfire, Teleport, and air grab. He has the leg sweep too, but, I don't feel it's very dangerous at all outside of combos, it's incredibly predictable, even with mix ups. If anyone else has input to throw in on it I'm missing, please do so in your post, I'd like to hear how other Reptile's approach him. I'm going to describe them each individually, then describe how I approach the match up. I'm also going to address the tools we have against him.
Hellfire: I personally feel that Hellfire is one of Scorpion's more dangerous tools against Reptile, as to why I am addressing it first. Hellfire has a weird auto track function that tags us pretty late into an elbow dash. I tried punishing it with double elbow dashes on reaction, but, it tracked me mid way through my first one. A smart Scorpion will try to bait our dashes and shut it down with Hellfire, or, spear. If you're quick enough, I was able to jump and elbow dash as soon as I hit the ground to punish him. His other option with Hellfire is hitting us with it on wake up, since it's unblockable, but, every chance they did this, I was able to punish accordingly, whether it be with acid spit, or dash elbow dash. A dangerous tool we need to watch out for, but, nothing to hinder our ability to fight.
Spear: Spear seems to shut down a lot of opportunities as well, not just for Reptile. The best advice I can give about Spear is, if you see it coming, and you're not already committed to something, just do acid spit. While the spear will still hit you, as will your acid to him, getting you out of the spear's animation, and not getting you comboed. A trade to get out of a full combo is fine by me. The spears juice isn't the damage, it's the stun it gives, so, it's the better option.
Teleport: Teleports can be incredibly hit or miss against Reptile. Scorpions, while not one of the better teleports, it's still good, especially mid combo. If you are dumb with your counter attacks or AA's, he can make his jump ins safe with teleport. A smart Scorpion can really make his teleports tricky, especially if he gets a jump kick on you high enough he gets a free combo off a teleport land b+2 commence combo.
AirGrab: Scorpion has a multitude of options on a jump in, whether it be him or us jumping in. He can commence a combo, and it can wind up being incredibly damaging. Or he can just do a clean air grab, setting up options while you're grounded. While not his most dangerous tool, still gotta' be careful on our jump ins, at all times. If you're going to jump in, try to make sure you have enough meter for a breaker if he starts a full combo.
How I approach the match up:
Right when the match starts, we both are going to want to close distance. Be patient and wait for him to mess up, whether it be throw a spear or teleport, and punish accordingly. On teleport whiff's, you have enough time for them to land to start a full 3 2 1 bnb for full damage, assuming they don't use their breaker. He can keep a decent amount of pressure on you with his normals, but, nothing you cant counter with an elbow dash. Just always keep it in the back of your mind he can cancel most of his normals with teleport, so always be ready to block and punish it, just in case. Be careful with your elbow dashes, in fear of being tagged by a spear, and try to keep some meter, don't waste it on x ray.
Tools we have against him:
Acid Spit: As I stated earlier, we can use this to trade with spear. Be careful using it to zone, he can easily tag you on a mistake acid spit.
Elbow Dash: Gives us the ability to close distance, tag him on normal string mess ups, ground mix ups, and to get away from a teleport if timed correctly.
Slide: Haven't tested this, but does slide go under spear? I don't think it does. Slide also stuff's Scorpion's wake up leg trip, and slides you out of the way of a wake up teleport.
Forceball: Able to use this to tag him on spears too, while not as viable of an option, since you won't get a combo on them, and you might still be staggered. Haven't done a lot of testing with this yet.
Ex invisibility: Damage boost is nice, and makes him have to think if you're going high or low. Also makes it difficult to judge where you are on the screen, to properly space his teleports. Be careful though, even if Hellfire misses, still gives him an idea of where you are.
Green Hand: Able to tag him out of teleports if timed correctly. I think THTB said the timing somewhere, and if I'm not mistaken, right when the teleport starts, will the green hand auto correct if you input it right as Scorp is leaving the screen? If you do ex and instantly elbow dash whiff out of it, you should be able to land a combo off of it.
So overall, Scorpion has tools to fight against us, but if we play it correctly, it should just come down to pure skill.
50:50