League-of-legends – Crystal Scepter with Gangplanks passive

Rylai's is a decent pick on Vladimir, but ever since his nerf from his passive on the conversion of HP into AP I don't take it anymore and just focus on pure AP item like Rabadon's Deathcap.

But to answer the question, all of Vladimir's spells would proc Rylai's Unique ability, UNIQUE: Your spell damage slows the target's movement speed by 35% for 1.5 seconds (15% for multi-target spells and damage-over-time spells).

Which means, your transfusion would slow the target by 35% but the rest of your abilities since they are all AoE, multi-targeting spells, would only slow by 15%.

They changed it in a patch; now, "zombie" champions lose all their buffs and debuffs. I could not find the patch in question.

Here is a post asking a similar question.

Presently, Kog'Maw receives the speed boost over time from his passive, but Ghost will instantly vanish from the buff bar.