I don't play him much, but in the recent games where I have I don't remember drawing turret aggro from his W on an enemy champion.
If this is intended because it does no damage, then why does Yorick's W draw aggro?
Vistha Kai4 votesIf it ends up displacing a champion durning casting, it's possible to draw aggro, as with all player-created terrain abilities.
They are coded to deal 1 true damage on displacing units, same with Zilean bombs which also draw aggro on being placed despite not doing damage at the time.
Otherwise all non-damaging abilities do not draw aggro.
DeathBurst1 votesYou sure about "all player-created terrain"? 'cause it's specifically mentioned for Trundle's Pillar, but I don't remember ever seeing it mentioned for Anivia's wall, and Azir/J4 ults actually deal damage.
EDIT: my bad, it's actually mentioned for Anivia's wall too. My memory is just playing tricks on me ^^'
1374341 votesI believe Aniva's wall draws aggro is the enemy touches it.
DrCyanide1 votesIt wouldn't surprise me if Yorick's wall has the same 1 Damage that other player created terrain has.
EndlessSorcerer1 votesIIRC, player-created terrain (i.e. Trundle Pillar, Anivia Wall) will draw tower aggro upon hitting a player even if it doesn't deal damage.
Nasus' Wither is more similar to Fiddlestick's Terrify, Zilean's E or Lulu's Polymorph than anything else since they are all targeted, non-damage CC abilities.
Sadly, I can't remember if those abilities draw tower aggro.
Ralanr1 votesWell that answers one question.
DeathBurst1 votesOnly damage draws tower aggro. Player-created terrain actually deals 1 True damage to enemies they knock-back specifically in order to draw aggro. (I thought Trundle Pillar was a special case, but it's actually the common rule, TIL.)
CC-only abilities won't draw aggro.
EndlessSorcerer1 votesFor some reason, I thought they recoded the abilities to let them grant assists and draw aggro without dealing 1 true damage to the target.
Eh, close enough.
1374341 votesThey did, at least for Zil, and I believe Aniva's wall. I don't know if that coding was ever applied to Trundle's pillar though (Zil's code was being changed for his mini reworked).
Big Lincoln1 votesbecause yorick's W displaces people if they get bumped by the wall, which like 
E draws aggro
DeathBurst1 votesYeah, only damage draws tower aggro, so Nasus slow doesn't.
And hum, about Yorick, the W is the blob or the wall?
Yorick's blob does deal damage, so it's normal. For the wall, maybe they special-case'd it, similarly to Trundle's Pillar which deals 1 True damage (not mentioned in tooltip) just to be sure it draws tower aggro. Never heard any mention of it before your post, though.
Ralanr1 votesW is the wall.
UberAffe1 votesMost "purely" debuff abilities actually deal 1 damage so if you are in turret range while you use it the turret will aggro to you.
InfernoFøx1 votesNo they dont. They deal 0 damage. If you wither or other form of CC that doesnt do damage, its says in death recap (effect status) and doesnt have any form of damage. So things like that dont deal damage.
UberAffe1 votesdeath recap is notoriously bad for information. That said I guess I don't know for a fact about all of them but I know trundles pillar does 1 damage.
InfernoFøx1 votesnever noticed that
