Malphite spams his slow early and has a sweet knock up later. Malphite deals magic damage. I'd say ideally you want someone with good burst damage, preferably AD so opponents in the lane can't shut you down with MR, and with their own stun/slow.
Xin and Irelia are both good choices that Arch mentioned, I could role with those options.
Panth is another obvious answer. Massive early and late game power, leap/stun, lots of bursty damage, etc.
Urgot could be pretty sweet to add some range into the mix. Pretty much anyone with any kind of cc in a lane with Urgot and the other team is going to get zoned and ganked. Stacked slows and loads of damage. Problem is Urgot still doesn't turn into a whole lot when farmed in my experience.
Nasus could be pretty good too, stacking slows with Spirit Fire under them.
Swain could work for Snaring after Malph slows and than LazorBird. Could make for some killer surprise ganks.
Yeah, I'd say both Irelia and Panth are the best options, they are hard to harass, can get a lot of burst early on and devastate later, and both have stun/slow's to compliment Malph.