Let's see who gets this answer right first.
EDIT:
And the winner is....Meta Awesome.
Pillar = Knock Up, Slow, Impassable Terrain
Or maybe
's Gravy Field = Slow, Knock down, Stun, Center Drag
Sion ult? You can cc yourself and up to 5 enemy champions every 36 seconds with 40% cdr
Nasus Wither?
Malzhar/WW suppression?
Gnar?
Ashe Ult.
Alistair Q? Knockup + 1 second stun?
Or Akali Shroud, 8 seconds of slow.
Morg ult.
Morgana snare. Actually get afk warnings because of that shit.
Lee's ult a targeted knock back that knocks up others over 10 temmos.
A random skill of Riven.
She makes the enemy player go afk to flame or to despair usually.
Blitz pull under his turret
Whoa I thought someone would have figured it out by now. It's not any of the answers listed so far.
I am shocked to see no mention of 
's disgusting CC station ultimate, like how?
EDIT: Ah I am so glad to be wrong, there is 1 mention! Thank god I am not alone here. EDIT2: Someone said Bard's R and they would most likely be correct. I just tend to ignore the CCs that work both ways as it's too unreliable.
Whatever you're thinking, the answer is obviously Bard. He can stun all 10 players at one time.
Pillar = Knock Up, Slow, Impassable Terrain
Or maybe 's Gravy Field = Slow, Knock down, Stun, Center Drag
?
?
stifle 3-sec silence and buff removal
irelia's passive-up to 40% tenacity
lissandra ult-zhonya's/stun for 2.5 seconds + 40% slow
nautilus? misread, let me think again no idea... cho q?
--> R
Death is the best CC
