Hi, all! Seeing the term, "Tanknivia," you might assume this is a "troll" or "fun" build... And I encourage you to play it as such, if what you're looking for is a silly build to enjoy using in ARAM or Co-Op Vs. AI! However, if you're more of a serious business player... fear not. This is the Anivia build I use in ranked matches. If you're competent at landing skillshots and have good instincts about where to place walls, you can and will rip your opponents to pieces in 5v5 ranked using this build. =)

So... Anivia's an AP carry champion, right? Of course. That's how everyone builds her. Why, then, am I singing the praises of a "troll" build?

Well, the following are my reasons for building Anivia the way I do:

Tanknivia trades on having high maximum mana. By the time you reach level 18, you should have 3462MP with the 'balanced' final build. Rod of Ages, Archangel's Staff, and Frozen Heart grant 2150 of this; Anivia's base mana and her mana per level account for the rest.
Any Anivia guide you read will point out just how quickly Anivia runs out of mana. What with the new changes making MPregen items based on the champion's (in this case unimpressive) base mana regeneration rate, Chalice of Harmony is the answer to your prayers: rather than being based on base regeneration rate, it uses a percentage of your missing mana; so your high MaxMP means that the Chalice alone supplies enough mana to power a perpetual glacial storm once you're nearly out of mana.
The other main purpose of having high max mana is that by the time you reach late game, assuming you've built Frozen Heart rather than Iceborn Gauntlet and haven't yet upgraded Chalice of Harmony, your AP is at 244 from just two items -- Archangel's Staff and Rod of Ages. Having AP from items like Athene's Unholy Grail or Iceborn Gauntlet just makes you scarier.

If you ask most people what the signs of a good tank champion are, they'll usually say that in addition to being hard to kill, a good tank requires at least two of the following: crowd control (CC), a damage threat, mobility, and area deny (the ability to make opponents afraid to enter a zone.) All of these things make it harder for an enemy team to target carries; a successful tank practically forces an enemy team to wait until they're dead or elsewhere before initiating any sort of fight.

Crowd Control and You!
Anivia has ridiculously good CC and area deny for a champion who most people see as an AP carry.
[*] Flash Frost is a (small) AoE stun and slow combined; it doesn't stun for a long time, but its range is fantastic and its AoE nature makes it very useful for stalling a bunch of enemy champions who are chasing your teammate in a mob or fleeing in a clump. It can also serve as a good long-range interrupt for enemy ultimates, such as those of Malzahar, Galio, Nunu & Willump, Miss Fortune, etc.
[*] Crystallize, of course, is all CC; it does no damage whatsoever, doesn't scale with AP, and has a fairly long cooldown. So, logically, the best way to use it in a teamfight is to actually live longer than 10 or 15 seconds, and get two or three walls up instead of just one.
[*] Frostbite is Anivia's bread-and-butter damage threat. Against a chilled opponent, it has an AP ratio of 1:1, and Tanknivia may not have 700 AP but she does have 200+ from Rod of Ages and Archangel's Staff alone.
[*] Glacial Storm is a massive AoE slow that ignores Tenacity effects, is spammable, serves as a zone deny, and synergizes well with any other AoE effects your teammates may have.

So you've spent the early game farming, and finally bought the Core Build items above. You've got your tankbird. "What," you ask, "Am I supposed to do with this odd item set that you've told me to put on my mage?"

Simple answer: now you get to stop playing like a mage.

The Damage Threat
Anivia has ridiculously good base damage on her Flash Frost and Frostbite, both of which will act as though they had a 1:1 AP ratio in certain circumstances ( Flash Frost if you deonate it after it passes the opponent, causing it to hit them twice; Frostbite if you use it on a chilled foe, which you should always be doing.) Because of this, Anivia doesn't NEED to have 700 AP to melt squishies, which is why the aim of Tanknivia, in late-game at least, is basically "Rush in and kill Jinx/ Miss Fortune/(Insert Squishy DPS Here) while completely ignoring the enemy's tanks and drawing all their CC."
Then you get to watch as your team demolishes the rest of them (possibly from the safety of your ridiculously bulky egg, assuming you aren't still sitting comfortably in the middle of the enemy team with your Glacial Storm up.) ^ v ^

To reiterate, Tanknivia doesn't need to melt EVERYONE on the enemy team; just the ones who have very little HP and Magic Resist. If you've forced one of their carries to build extra survivability just to counter you... Then you've done your job, because they have that much less DPS for late-game; and you'll still be laying down cc on their entire team like a boss.


Laying Down CC:
This is the part where skill comes in: back in my early days of playing the bird, my opponents would cry about Anivia being a faceroll and requiring no skill... but these were invariably the people who, immediately after saying that, try to play her and promptly ragequit because they can't handle her walls and slow-moving skillshot properly. When out in the open, it takes good judgment to wall properly so the enemy has to take the longest route around, preferably straight through your Glacial Storm where they'll be less able to dodge Flash Frost.
In jungle teamfights, an Anivia can be a menace to her own team if used poorly; a skilled Anivia, however, can trap one or two members of the opposing team on one side of a wall with her carries, while the rest of her foes descend into chaos trying to Flash through the wall or run around it. Against squishy Anivia, the isolated opponents in question could simply rush her, egg her (or kill her if the timer's down) and run; in contrast, Tanknivia can keep them perma-slowed and force them to waste CC on her to chase; and she'll survive until her team can spring the trap.
The best part is that until an opposing team notices what you're building, they'll keep acting as though you're a squishy wizard; after all, squishy is how everyone builds her!


Using Your Eggs Well -- Rebirth:
The egg's not of much use in the early game if you're ganked by the enemy jungler and don't get to the safety of your tower in time. But that, of course, is common sense: Beware of being ganked early. However, in any kind of teamfight, your egg is basically an instant global taunt for the enemy's DPS. Nobody can resist the allure of scrambled eggs-- after all, you're just sitting there helplessly!
Squishy-build Anivia will die very quickly as an egg, meaning that the egg is only useful when your team is RIGHT THERE to help you.
The same goes even for Tanknivia... IF she's ganked by 3+ of the enemy team and her allies are nowhere nearby... In other words, if she gets outplayed. But in most conditions, you WILL revive in time... and probably kill one or more of your opponents if they were at all low on health pre-gank.
In a teamfight, if the enemy team is busy piling the egg, your true carries are free to rip ruthlessly into their life bars. And if your opponents wise up to your tanky nature and ignore you when you get egged? You'll be up eight seconds later, with all your skills off cooldown (except perhaps wall) and ready to help your squishies escape or chase with some AoE slow and stun.
Turn this to your advantage; once your team starts roaming, assign yourself to guarding a squishy carry or a damage-heavy bruiser who's capable of punishing enemies who try to chase you; serve as bait if you're at low HP, peel for your carry, or trap a victim with one of your walls, and your team will love you.
Enjoy playing Tanknivia, and remember...

"Stay cool."