"Make it rain."
The Fat Stacks is a unique, novelty weapon unlocked by attaining the Rolling in It achivement. Releases several dollar bills that will stop mid-air, and slowly descend on the ground down below.
A novelty item, the Fat Stacks may be a bit tricky to use if one don't master it's flight pattern. When about halfway through their trajectory, all projectiles will stand still, then slowly descend on the ground below, dealing damage to the enemies. If fired below then 0° Angle, the projectiles will return to the player after traveling a certain distance, making it difficult to use this weapon to directly damage the enemy, such as RapidFire, unless the enemy is very close to the player. The dollar bills are affected by the wind.
If used properly, it's capable of dishing high amounts of damage on a single target, or over several enemies packed in an area.
UpgradesThe two upgrades are Dolla Bill and Make-it-Rain.
Each of them will increase the amount of projectiles in the dollar bundle.
In order to get this weapon, you must save up a total of 1,000 Gears in your inventory. To achieve this quickly, it's not recommended to waste any Gears at the Store until you have amassed the required gears. After unlocking the Fat Stacks you can then proceed to waste the gears on the store as you desire.
To speed up the procedure, try to pick up as many Gear boxes as possible in the games, and be lucky enough to grab 100 Gears in the Daily Gift.