as kat I HATEEEEEEE miding against malzahar... after 6 he ults me than ..

Annie, Fiddlesticks, Malzahar, Garen.. even Janna!

Basically any character that can hard CC I suppose (Stun, Silence, Knock up). They are all bad for her ultimate.

Sion - See if you can get him to push the lane and overextend. Its very easy for him to do if he is farming with his bubble instead of last hitting. Then gank him hard.

Past that, he is one of the best solo's in the game if the player is solid. Try to whittle when you can if you have range in between shields. Try to gank before he gets all hp back off his ult past 6

1 v 1 against kat, maybe annie, kass 4 sure, a good malz. . .
in a team fight where everything is hectic and i saw some misclicks on my (kat's ult) shen's taunt is by far the best, he always saves it for kat :/
as for the sion build:
mp5 yellow
2 mp5 quints, 1 cd per lvl
cd per lvl blue
mag penetration reds
(u can keep the shield up at al times with this mana regen, and hold a 1 v 2 easy)

dorans ring
sorc boots
rush rabadon
morelos tome ( u will have 40% cd and can spam the shield and stun)
thats my core
then u can go with some survivability if they focus u, more ap, or whatnot, but after u get the core item its gonna go downhill from there, they start tankin up , stackin mr etc

ghost+flash
in team fight use shield + stun and back off, wait 3-4 sec 4 them to be back on and go nuke another guy, dont even think about auto-atackin them

p.s. they nerfed his stun and it does sometime make the diferance

Fiddlesticks, Blitzcrank and Malzahar give Kat the most grief. In a 1v1 lane, I would say Malzahar is the best option.

If you mean 1v1, then anyone with CC.

Malzahar, Annie (assuming Pyromania stacks), Kassadin, Feedersticks (Q + E), Garen, Tristana (Knockback), Janna (Knockup, knockback), or people with blinks that can harass at range like Ezreal.

In a teamfight scenario... you better have someone with crowd control and you better not be stupid enough to blow it all up before Kat comes in.

I play a lot of Kassadin and he works well...though having a katarina on the other team means that you have to save your silence until she uses her ult...generally it can mess up the timing of your burst damage on anybody else on their team. He will counter her very well, but it also limits Kassadins true potential

Anybody with a good interrupt will work for team fights...someone mentioned that blitz has 3 interrupts to use on her and he is an offtank type so he is probably perfect. If you can get a support that is saving their intterupt just for kat's ult that is ideal...Sona's ult, Soraka's silence are the two that pop into my head. If you consider alistar a support him too...

As Irelia I destroy Kat in a 1vs1 if she doesn't escape with Shunpo first (which she usually blows getting closer to me). I just wait for her to ult, stun her, then proceed to mutilate her face. Only time it's ever close is if I'm not quick on the stun, because man her ULT does a lot of dmg fast.

Due to how Ragnarok works with Death Lotus, at 6 (provided you're above 40% health or so or something), Olaf is basically impervious to Death Lotus. Now I wouldn't suggest going mid with Olaf, but in general, you can walk through Kat's ult if she's not fed and splatter her pirouetting ass against the wall.

Tristana can go toe-to-toe with Kat early game; if she Shunpos onto you as Trist, Explosive Shot and shoot her back. This is also a general mode of operation when playing against Kat: if she tries growing some balls and Shunpoing up to you, harass her back! She'll be a lot less keen to do anything when you've showed that you're not to be ****ed with. At 6, Tristana has Buster Shot to knock her back during Death Lotus and Rocket Jump to hopefully get away in time.

Vlad can sort of trade blows with Kat early game. If you're both 6, you have Sanguine Troll to get out of Death Lotus, provided you didn't blow it earlier. Afterwards, do the ol' Vlad Shuffle: Hemoplague, Ignite, Transfusion, whatever the hell it is that Vlads do.

Udyr's also great, although as a general counter rather than 1v1'ing at mid. Bear Stance allows you to slap her out of her ult, Turtle can mitigate a fair amount of damage, and if you're covering a lane and she's getting up in your face, just smack her back. You're Udyr, you can do that.

The other counters have been mentioned quite a bit in this thread already.

Yeah, if you just mean a general overall counter to her all match, you want someone with a spammable stun/pop-up. Allistar, Blitz, Udyr can all shut down her ult almost instantly. Renek and Irelia also, can get to her quickly and stun instantly.

If you mean hard counter her in lane, you'll want someone that can make her pay for Shunpo'ing close while also being able to farm creeps without taking too much bouncing blade harass or can heal through it. I'd say Gragas, Jarv, Malphite, Sion, Morde, Chogath, Annie, Shen, Sivir (If you're quick with shield), could all give her trouble in lane if they're quick.