Arena Closer

For the event upon spawn of the tank, see Arena Closing.
 * Nickname=AC(Commmon)}}

The Arena Closers appear when a match of Domination or Tag Mode or is finished or when a server closes in Free For All, Maze or Team Deathmatch. It is playable in Sandbox mode, when using the \ key several times (it is after Necromancer).

The purpose of Arena Closers is, as their name implies, to close the server; players killed by Arena Closers are then kicked from the server, then the server reboots when all players are killed off the arena. However, if the player manages to survive them (e.g. by activating God Mode on Sandbox), the player will still get kicked out from the server after a couple minutes.

Design
The standard Arena Closer features a large yellow circular base with Basic Tank's Barrel but proportionally shorter. It is about as large as a Dominator, and the bullets it fires are about as large as an Annihilator bullet. In the Sandbox mode, it takes on a blue color, and is several times smaller than the average Arena Closer. The yellow variation's color is same as the Squares' and summoner's. The yellow variation is the largest Tank in the game.

Spawning
Several Arena Closers (with a maximum of 16) will spawn when a Domination or Tag Mode match is finished. In 2 Teams,4 Teams,or in FFA, the Arena Closers appear when only a few people are in the server or when the game is being updated. In Maze when the server has been up for 5 hours. Arena Closers may spawn outside of the boundaries of the map, in which case they will immediately target a player and move inside.

Behavior
The Arena Closer's priority: When they attack, they will shoot at the target. When all targets are dead or neutralized, their AI has no reason to continue to fire, so they'll be spinning and slowly drifting in a random direction.
 * Any and all players still alive.
 * Any non-neutral Dominators.
 * Bosses that are in team grey (Fallen bosses).

Stats
The Yellow Arena Closer has:

In Sandbox Mode, the playable Arena Closer has the health of a normal tank, but its bullets are still far more powerful than that of any other tank, approximately equal to a real Arena Closer.
 * Larger bullet size than an Annihilator.
 * Infinite Penetration and the Damage
 * The Bullet Speed of an Assassin.
 * The Movement Speed similar to protectors.
 * The Reload of a maxed Reload of the Basic Tank.
 * An unknown amount of health either due to having god mode or a LOT (infinite?) of health.
 * Complete resistance to Damage knockback because of god mode or a passive setting.

Miscellaneous
The Arena Closers aren't targeted by the Protectors until the Arena Closers accidentally shoot or bump into them. The base itself has no effects on Arena Closers. Also the AI Dominators, Bosses and Crashers don't target them. Their body and bullets can't harm shapes, the neutral bullets will just go through them, and the Arena Closers themselves will just push them out of the way. The Arena Closers and their bullets can go through the Maze game mode's walls. Also the Arena Closers can go through each other.

Playable Arena Closer:

 * Weak Against: Dominators
 * Strong Against: Every normal class

As the Arena Closer
There is no real strategy to use when playing as the most powerful tank in the game. However, you must be vigilant when other Arena Closers are present in the server, as they are one of the few tanks who can easily defeat you. Outmaneuvering them is usually the best option, but in a perfect 1 versus 1 situation, the winner is usually the Arena Closer who gets the first hit.

Against the Arena Closer
Arena Closers in the Sandbox Mode can only be easily taken on by other Arena Closers. Other tanks with massive health pools, such as Dominators, may stand a chance, so long as they are careful to stay far away. All other tanks will be quickly destroyed.

If it is distracted, with a Ranger / Stalker or Streamliner, you could have a few chances to kill them at range since you have better FoV.

Real Arena Closer

 * Strong Against: Tanks out of god mode
 * Weak Against: Tanks in god mode, Polygons

Yellow Arena Closers are essentially invincible, so fighting them is not an option. Escaping is virtually impossible, as they are faster than the Fighter, Sprayer, and Booster class, even with fully upgraded Reload and Movement Speed combined. But they cannot kill someone in Sandbox Mode if they have the God Mode on since it means invincibility.

History

 * Despite their strength and speed, their name tag used to indicate that they're only level 1.


 * On July 31, 2016, the Arena Closers' spawn was delayed after the message, "Arena Closed: No players can join"
 * The Arena Closer was the first AI-controlled tank in the game.
 * It was originally much easier to escape the Arena Closers, as both their Movement and Bullet Speed were much slower than they are today. Some were able to survive their onslaught with maxed out Movement Speed, Reload and Bullet Penetration.
 * They were buffed to their current strength and speed in the same update that added the Domination Gamemode.
 * They were buffed again to being a lot bigger, so they can deal Body Damage, and it now shoots a bigger bullet that is the size of an Annihilator's bullet, making it harder to dodge them.
 * As of September 3rd, 2016, with the addition of Sandbox Mode, Arena Closers are now playable tanks, but ONLY in Sandbox.
 * Since September 6th, 2016, they now have scores, and when they kill the Bosses the notification doesn't state anything about "an unnamed tank" anymore.
 * Since September 25th, 2016, the Arena Closers can go through Maze walls.
 * In an update, Arena Closers were no longer pushed back by damage. During the same update, they were given unlimited bullet penetration
 * Also when all players are killed or left, they will attack the player-controlled Dominators.

Trivia

 * Aside from its yellow color and shorter Barrel, an Arena Closer's design is very similar to that of a very high level basic Tank which is slightly smaller than a Mothership so its level might be 140 or slightly lower.
 * If you are killed by an Arena Closer, you don't actually go to a new server, you just enter the renewed version of the same server. This was probably meant to prevent the game from getting massive ping freezing from redundant servers.
 * When something is shot by an Arena Closer, it seems to "fall" to one side before it is killed because of the Arena Closer's extreme bullet knockback.
 * Arena Closers may spawn outside of the regular map boundaries. However, upon spawning, they will move inside the map boundaries (since their AI will target a player inside the map, and will proceed to move towards them).
 * Before, they spawned in the center of the map.
 * Arena Closers sometimes merge with other Arena Closers because of their 100% knockback resistance.
 * There was a glitch where Arena Closers AI broke, making them slowly drift like Polygons even if there are players left.
 * In sandbox, the Arena Closer is just after the Necromancer when you use the \ command. This is due to the Arena Closer being the last added tank when Diep.io was released, and the Necromancer being added next.
 * Base Protectors can pursue and attack Arena Closers,however protectors PPAwill die upon impacting their bullet/hull.
 * It has become a game in itself to try and survive the barrage of the Arena Closers for as long as possible.
 * You can survive the Arena Closers in Sandbox mode by opening a Sandbox arena, playing it as someone else, leave as the host, and enter God Mode as the other player.
 * You used to be able to survive it with a team of Mega Trappers and Hybrids until they were buffed to have unlimited bullet penetration.
 * It's unknown that what is the final fate of them upon the reboot of the server.