Talk:V1.0.0.114/@comment-199.64.0.252-20110329184039/@comment-3508137-20110331075025

"Slowing effects can stack, but only the strongest slowing effect from each source (item, ability, neutral buff) is taken into account at any given time; the others from that type are ignored. Slows are applied before speed diminishing returns, and only the largest slow gets full effect. Others are stacked multiplicatively at half value => now it reduced to 35% of its value."

So as you said at Urgot case with Rylai's crystal scepter and lizard buff. With W buff and hitting Q, he will have 40% slow fully from his W(biggest slow kick in fully), 35% of 35% multiplicatively(slow from rylai's), and finally 35% of 15% slow from lizard ( if urgot ever has chance to auto attack). And there really is no slow from urgot's E (AOE acid spell) because it will be replaced as soon as you hit your target with Q(Only 1 source from slow kick in- so doesn't matter if you buy Frozen mallet + rylai there is only one that will work). It's a lot harder for a person to get slowed to oblivion from just one other person.