Stalker

The Stalker is a Tier 4 Upgrade and is one of the final Upgrades of the Assassin Class.

Design
The Stalker features a circular base with a single long, skinny, trapezoid Barrel.

Technical
The Stalker has the ability to become invisible when it is immobile, with a short fade-in and fade-out time (approximately 2 seconds); which is an ability unique to itself, the Manager and the Landmine.

When invisible, if the Stalker moves in any direction, or after shooting two consecutive shots, it will immediately lose its invisibility. Additionally, if the tank is damaged from any source, it will lose some of its invisibility and enemy Bullets making contact with the tank will interact normally and dissipate prematurely. Lastly, if a Stalker is at the top of the Scoreboard, the Leader arrow will still point to it, even while invisible. These are the only ways for enemy tanks to know the location of a hidden Stalker. It is important to note that shooting once while invisible will make the tank lose some invisibility, but with a shorter fade-in time, and enabling Auto Fire will remove invisibility permanently until disabled.

Similar to all other tanks in the Sniper branch, the Stalker has increased Bullet Speed and a greatly widened field of vision, with the trade-off of a fairly slower rate of fire when compared to the Tank, however, its field of vision remains the same size after it is upgraded from the Assassin.

Strategies
Avoid Melee Class or High Max Health and Body Damage. With their defensive, They can kill you.
 * Strong Against: Unsuspecting tanks, slow tanks, low DPS tank
 * Weak Against: Prepared tanks, high area denial, fast tanks, high DPS, Melee Classes 

Tips and Tricks

 * One can maintain their invisibility by moving slowly, but not too fast. When you move slowly, you will only slightly uncloak, which makes it hard to notice for the enemy.
 * The Pentagon Nest is the riskiest but most rewarding area to camp in. It is a popular area for many players, and you can simply hide there and kill off stronger players while their attention is focused on the Pentagons.

As the Stalker
Players won't notice Stalkers when they are invisible. As such, some builds use full Body Damage and Max Health Stats to let people just run into you and die seemingly out of nowhere.

Stalkers have decent Bullet Speed and Penetration, so don't prioritize those two. Usually, the things you want are; Reload, Body Damage, Health Regen, and Max Health to stay alive and bump the small tanks.

Using a ram Stalker requires patience and proper positioning. Try to place yourself near areas where it can usually be crowded and wait until someone runs into you or is near you. If there is no target, reposition to another location.

Stalkers require patience sometimes. You may have to sit and wait for a while before you find an enemy. Alternatively, if you want to play annoying, you can simply wait until someone strays too close and pop out of nowhere, surprising them and getting a headstart shot off.

On the August 10th update, the Stalker and the Manager's invisibility were not nerfed with the Landmine's, keeping Body Damage or Bullet Damage Stalker a viable pick. However, they are revealed if they are shot at while invisible.

The Stalker is occasionally a better alternative to the Landmine, as it can cloak quickly and has a cannon to try and finish off weaker enemies. However, compared to the Landmine, it trades off with slower Movement Speed and regular Stats, forcing the player to put spare stat points into another Stat.

Against the Stalker
Stalkers are completely invisible when they hide. If you see a Stalker going invisible, try to remember where they are and then kill them. This works well if you are a Destroyer type of a tank. Don't ram a Stalker unless you have good Body Damage and are a high Level. Many Stalkers ram other tanks when they come near.

Bugs

 * On the Mobile version, the Stalker just switches from invisible to visible mode instead of fading in and out, allowing for instantaneous cover.
 * The Stalker, used to be faintly visible when cloaked. When players switched their screen color, they would be able to see them, so the Stalker was made completely invisible.

Trivia

 * The Stalker is the only Class to have its Upgrade selection button's background color changed.
 * The Stalker is the first tank to have the ability to go invisible.

Imported Information
''Note: This section contains information imported from the Official Diep.io Wiki. Feel free to add any information contained here to the main page, but please do not delete this section. Thank you.''

Technical (Import)

 * The Leader arrow will still point to your location if you are a Stalker.
 * FOV and movement speed are also increased. (Note: unlikely, probably false)
 * Fade-out time is 2 seconds.