Whimsy: On my ally or my enemy?

Active – On ally cast: Target allied champion gains 35% movement speed and bonus ability power for 5 seconds. 

Active – On enemy cast: Polymorphs an enemy champion for a short duration, disabling their ability to attack or cast abilities and reducing their base movement speed by 60. 

This is Lulu's W.  It's possibly the hardest-to-use targeted ability in the game.  Should I CC my enemy?  Or is it worth it to speed-boost an ally?  This article will give some specific situations in which you should do one, criteria for deciding which one to use, and then conclude with some mini-case studies that illustrate different decisions you might make in complicated situations.

Rule of thumb: Polymorph when you need to stop unkitable damage or prevent a spellcast.  Otherwise whimsy an ally.

Times you DEFINITELY want to polymorph:

• There's a really important channel to break.  This could be Kat ult, Fiddle drain, Warwick ult---if the channel is teamfight-altering, break it.
• You need to stop the enemy's damage RIGHT NOW.
• The enemy is about to dash over a wall that you can't get over.

Times you DEFINITELY want to ally-cast:

• You're attacking a tower and there's no chance of an enemy coming by any time soon.  Cast it on the AP champion with the highest AS.
• You're too low to safely get within polymorph distance of an enemy.
• You're chasing an enemy that doesn't have any mobility skills and aren't scared of any incoming damage.
• You're leaving well to go back to lane and there's no chance of a fight in your jungle on the way. 
• You're warding/ward-clearing and the entire enemy team is on the other half of the map.

Things that would encourage you to enemy-cast:

• The enemy has a mobility spell available.
• The enemy has a CC spell available that you want to prevent.
• Any other situation that would call for a silence.
• The enemy has a noticeable amount of damage relative to you/your teammates.

Things that would encourage you to ally-cast:

• You're chasing or running away.
• Someone on your team is kiting.
• You're not all that scared of their damage, and you have an AP mage with cooldowns available.
• You're taking an objective.  (At the very least, Whimsy yourself before you E and Q, if you have enough mana.)

Now let's look at some case studies.  They're combinations of real-game situations with some of the details made up if I forgot them.

Case Study 1.  Lulu is running from well to help her team take dragon.  Xin Zhao and a couple teammates aren't taking too much damage from the dragon, and everyone's roughly level 7-9.  However, the enemy had dragon warded and engage on Lulu's team after they finish the dragon.  At this point, Lulu is passing double golems.  One of her teammates died, and Xin is having a hard time fighting.  Lulu knows if she can get there in time to ult Xin and polymorph Udyr, then Xin will win the fight.  She decides to hold her Whimsy thinking she could get there without it.  Unfortunately, she gets to dragon about two seconds after Xin falls.  The correct decision would have been to Whimsy herself to guarantee that she could get to the fight on time; the ult on Xin might have been enough to turn it around and kill Udyr.  This is a situation where you need to be very aware of how much damage other champions are able to do to each other in order to make an informed choice.

Case Study 2.  Lulu and Draven are fighting Sona and Tristana in botlane.  They won a fight at level 1, so they're somewhat ahead of their opponents.  Lulu is standing on the far side of the enemy creeps to zone Tristana and Sona when Tristana jumps on her to engage.  Everything is warded, so Lulu feels safe from jungle/mid ganks.  Instead of polymorphing Tristana, she decides to speed up Draven so that he can close the gap between them more quickly.  By shielding herself, she's able to barely survive Tristana, flashing out at the last instant before Draven picks up the kill.  Here, Lulu realized that the amount of damage she could prevent from Tristana wasn't worth the amount of damage that Draven would effectively be losing by not quite being in autoattack range yet.  She also permitted Draven to chase further.

Case Study 3.  Lulu and Annie are laning botlane, both level 6.  The enemy Draven is pushed almost to their tower, when their jungler Skarner starts to come down for a gank.  Annie flashes for a stun onto Draven, who has his flash available.  Lulu has two choices: Whimsy her Skarner so he can get in range to ult chained with Annie's stun, or polymorph Draven so that he is unable to flash out, hoping that they won't have to burn the Skarner ult.  Lulu decides to whimsy Skarner because if it turns out that the ult is also necessary, this way he'll be able to pull Draven significantly further during the duration of the suppress than he would without her MS buff on him.  Lulu is relying on the assumption that they'll be able to kite forward as Draven is being pulled back, so if he flashes he'll still be in damage range of her and Annie.

Case Study 4.  Miss Fortune, Lulu's ADC, is fighting Tristana, the enemy ADC.  Miss Fortune is significantly ahead of Tristana at this point, and Lulu and MF have chased Trist almost to her turret.  Tristana's jump isn't available to her, so MF is going to try to dive turret.  Lulu is in range to polymorph Tristana or to whimsy Miss Fortune.  Lulu is not level 6 yet, so she won't be able to ult MF, but she has been leveling Help, Pix! first, so she'll be able to provide a decent shield.  She also doesn't have flash or exhaust available, so she won't be able to flash under tower and make sure that she's the one who takes aggro nor will she be able to reduce Trist's damage.  Because MF has two Doran's blades, Lulu decides to use the ally cast, thinking her carry will have enough HP to survive the dive even with Tristana able to output some damage.  The extra movespeed here is not important so much because it lets MF catch up to Tristana, but rather because it lets her get to the other side of the turret to lose aggro sooner.  Now Lulu is able to take a tower shot as MF dives again, picking up the kill on Tristana.


I'll probably come back and add a few more case studies at some point, we'll see.

And an update on what I've been doing---I finally got my Sona guide approved on the solomid site!  I had to make a few major revisions to it (mostly reorganizing the sections and getting rid of the silly icons that I hated anyway) so that took a while.  I'm also starting a Nami guide, which I'll hopefully be able to publish within two weeks.  It won't be as detailed as the Sona guide, but it should still be pretty good.  And I've been running the NA SNSS, VoDs of which are available on my stream.  My 2v2 tournament will be back next week, as will the SNSS!