Update:
With the Marksman updates on patch 5.22, the AP ratio on Caitlyn's Yordle Snap Trap has been removed, so this build is no longer viable.

RipR here, and I'm proudly presenting to you my AP Caitlyn guide for ARAM (and ARAM only). She's got two spells that scales pretty well with AP, Yordle Snap Trap and 90 Caliber Net. I promise you that at the end of your game, the enemy team will hate your delicious cakes more than Teemo's shrooms.

Now before we begin, let's get off on the right foot: don't use this build on Summoner's Rift, AP Caitlyn is as viable as an AP Garen on this map. But why should you play AP Caitlyn on the Howling Abyss on the other hand? Because on this map, you actually turn AP Caitlyn's weaknesses into strengths!

First, one of her flaws is that you can't spam Caitlyn's Yordle Snap Trap like Teemo's Noxious Trap or Shaco's Jack In The Box, you can only set a maximum of three traps. So it was a bit of a misleading advertising when I said that there was going to be a minefield of cakes, sorry ... But that ain't a problem on the Howling Abyss!
The narrowness and the corridor-shaped aspect of the map will make the enemies fall into your traps constantly, whether they like it or not. Even if you could, you won't even have time to set a fourth trap even.
Walking in your traps all the time means constant damage over time but most importantly snares, that will often be deadly for the enemy.

What is more, everything that Teemo and Shaco do, AP Caitlyn can do it too.
Booby-trap the bushes, the Health Relics, but also the walking paths! You can set your traps in the middle of the lane without minions accidentally ruining your minefield, unlike Teemo's shrooms.

No AOE spells, no farming spells?
You don't care for farming and pushing, your role is to destroy the enemy champions, sometimes without even being in the teamfight! (You remember, that sneaky little trap you set two minutes ago somewhere in the enemy camp? The dead enemy Twitch just noticed it too while wanting to escape ...)

Still not convinced about how AP Caitlyn can contribute to the team ?
How about looking at the damage you can do? Yep, never underestimate the power of the traps!



Still indifferent??? I know that's not true! But still, here's a pentakill with AP Caitlyn that should meet your expectations :

Pros

+ Complete control of the map, the bushes and the Health Relicss
+ Tons of CC and tons of underestimated damage
+ Free kills and assists even when outside teamfights or dead
+ An escape and crowd control ability that actually deals significant damage
+ Traps that are annoying as hell

Cons

- No AOE spells, no pushing abilities, weak auto-attack
- Can't burst down Champions, your playstyle is based on poking and damage over time

Usual masteries and rune page for a mage. You have spells scaling on AD, but you won't do deal much damage with them, so attack damage and armor penetration aren't useful.

Summoner Spells

Flash

The must-have Summoner Spell, even in the Howling Abyss.

Heal

I prefer Heal over Mark/Dash because you actually want to stay as far as possible from the enemy team, laying traps from afar as you are squishy. Heal can help you escape and survive.

Champion Skills

Passive - Headshot

You have no AD, so this spell isn't going to be useful apart from farming and pushing slightly better.

Q - Piltover Peacemaker

Little damage, but it is Caitlyn's only AOE spell, so you can use it to target all enemies and make sure to get all the potential assists.

W - Yordle Snap Trap

AP Caitlyn's bread and butter.
Good Caitlyn players use it to deal damage and snare enemies.
Pro Caitlyn players use it to control the map and the environment (See Setting your traps section of the guide)

E - 90 Caliber Net

Caitlyn's second spell that scales with AP.
AD Caitlyn use the recoil to dash towards the enemy in order to land a few more auto-attacks. As an AP Caitlyn, you'll deal more damage if you aim your net towards them, even if it means being knocked back. This spell makes a good combo with the Spellblade proc from Lich Bane.
It can also be used as an escape mechanism, as it knocks you back and slows the enemy at the same time, but this you already know.

R - Ace in the Hole

Even without AD, Caitlyn's ulti does pretty decent damage, good enough to finish low health enemies. Make sure there aren't any enemies between you two who could block your ulti and save his ally's ***.

Theoretical damage

Want to know how badass AP Caitlyn can be with a full build? Check this out stats using a full AP build! Keep in mind that it's only theoretical, magic resistance has to be taken into consideration and it's not recommended to build full AP glass canon.

Level up your Yordle Snap Trap twice to begin trapping the mid lane bushes before the minions spawn, to prevent the enemy from entering the bushes.
Also level up 90 Caliber Net once to have an escape mechanism ready in case.

At level 4, put one point in Piltover Peacemaker and leave it as it it. You'll only use it to target multiple enemies and to make sure to get all potential assists, so one point is enough.

Max Yordle Snap Trap as this will be your main damage source, and your enemies worst nightmare.

Upgrade 90 Caliber Net second to increase its damage.

Level up Piltover Peacemaker last.

As usual, level up your ulti whenever possible.

You should always try to have your three traps set on the map. If you feel an old trap isn't going to be useful, put a new one to replace it.
There are several strategic points for your traps :

On the lane

Caitlyn's traps can't be activated by minions, so take full advantage of it! Place strategically your traps on the enemy's walking path. Either they walk in it and get snared or they'll be forced to get round it and waste valuable time during teamfights (then eventually walk in it later on).



To force them to walk into your traps, place them in narrow locations, for example between a wall and a tower.

In the bushes

First thing you should do at the beginning of the game is rush to the mid lanes bushes and trap them! The enemy won't be able to go in and hide inside, and will be forced to be in plain sight, giving you the advantage. No more unexpected Nunu & Willump ulti!
This apply throughout the game. A Rengar without his bushes is cuter than Hello Kitty.

On the health relics

Same tactic as with Teemo's shrooms. Make them regret taking that Health Relic! Your traps will deal more damage than the Relic heals.

Sorcerer's Shoes

The best boots upgrades for you. The number of traps is limited anyway, so increased damage is better than shorter cooldown with the Ionian Boots of Lucidity.

Liandry's Torment

I love this item on AP Caitlyn for the same reasons Teemo does. It adds to your Yordle Snap Trap an additional damage over time of 12% of the enemy's current health (as he's impaired).
The double damage also works with the 90 Caliber Net.

Lich Bane

Excellent item for all unconventional mages.
As AP Caitlyn can't burst a high amount of damage on the spot, Lich Bane's passive helps her increase her damage during teamfights.

Morellonomicon

A good item that provides ability power and the mana regeneration you need. Its passive is also a good counter against healers and enemies who dare take Heal.

Athene's Unholy Grail

Another nice mana regeneration item.

Luden's Echo

An item with an overpowered passive as it is for the moment.
Each time an enemy activate your trap and you are fully charged, four additional nearby enemies also take damage.

Zhonya's Hourglass

Its active can help you survive assassins' burst if they are too annoying.

Rabadon's Deathcap

I tend to prefer the previous two +120 AP items, but Rabadon's Deathcap is the best item for tons of damage ©

Void Staff

Are the enemies too scared of you and beginning to stack magic resistance? Well, get the Void Staff and laugh at their corpses!

The Nope List

Abyssal Scepter

No, there will be times when enemies activating your traps would be too far away from you to trigger Abyssal Mask's aura.

Archangel's Staff

No, the game won't last long enough for the Archangel's Staff to be upgraded into the Seraph's Embrace.

Rylai's Crystal Scepter

No, Yordle Snap Trap and 90 Caliber Net are already crowd controls, you don't need an additional slow.

Nashor's Tooth

No, your auto-attacks are too weak for the Nashor's Tooth to be useful.

We want to rush the Liandry's Torment as fast as possible, so start buying two Amplifying Tome, a Ruby Crystal and three Health Potion.

Upgrade into a Haunting Guise. If you died too early and can't finish the Liandry's Torment yet, buy some Boots and some Health Potion.

After the Liandry's Torment, get a Lich Bane to increase your damage during teamfights.

If you spam your traps like I suggested, you'll notice that you are often short of mana. Time to get a mana regeneration item then! If the enemy team has heals, get a Morellonomicon, otherwise buy an Athene's Unholy Grail.

Get at least one of the +120 AP items between Luden's Tempest, Zhonya's Hourglass and Rabadon's Deathcap.

If the enemy team has too much magic resistance, finish with a Void Staff.

In order to get these screenshots, I had to use my smurfs accounts to increase the probability of getting Caitlyn as I had more chance winning lottery than getting her in ARAM mode.





Lucian and Talon were both IP farming bots, what were the odds? Still a pretty fun game even though it resulted in a defeat

Other Summoners

Michaljf

tacklab

Here are some videos of Youtubers playing AP Caitlyn. These were posted before my guide was published, so they don't follow my build : they are purely here to illustrate the play style of AP Caitlyn.

AP Caitlyn is a super fun and effective way to play Caitlyn in the Howling Abyss.

If you ever have the chance to come across Caitlyn in ARAM and have success with this build, you can also send me screenshots so that I can include them in the guide.

I'd be delighted if you can give me a feedback (either positive or constructive negative feedbacks) on the presentation of this guide or the build itself !