Call of Duty WW2 Zombies: How to Get Bloodthirst Tesla Upgrade Variation - needed for "Dark Arts" trophy & achievement.

PREPARATION STEP (BUILD NORMAL TESLA + LIGHTNING ROD DEFENSE):

Before you attempt this, do the normal main easter egg. You must complete the main easter egg up until the Lightning Rod Defense.

Step 1 (Let Bomber blow up the Laboratory Locker):
In the laboratory area (left side of bunker), there's a locker at the wall on the stairs. Those are the stairs next to the Schildblitz perk. It looks like a metal door in the wall. You must lure a bomber to it and let the bomber blow up right in front of the locker. This reveals a battery you can pick up.

Step 2 (Get Battery):
Pick up the battery from the locker and place it inside the laboratory trap (middle of the trap).

Step 3 (Simultaneously kill 2 x 2 Wstlinge with Laboratory Trap):
Simultaneously kill 2 Wstlinge with the Laboratory Trap when the Battery is lighting up green. You must lure 2 in the trap at the same time. You must do this a total of 2 times. So that's 2 x 2 Wstlinge = 4 total. Wstlinge are the big, slow brutes that charge at you when shooting them. It only counts when the trap kills 2 Wstlinge at the same time, killing just one of them does nothing.

Step 4 (Lightning Rod Easter Egg Step):
If you haven't already, complete the main easter egg up until the Lightning Rod Defense. Only after defending the Lightning Rods you can continue with the Tesla Upgrade.

Step 5 (Defend Battery):
Once the battery is powered up, pick it up (you'll know it's powered up because you can interact with it and pick it up). Insert it in the machine in the laboratory that previously gave you a part for the normal tesla gun. Hold the interact-button to close the hatch. Now you must defend the battery for about a minute or so. Zombies will attack you and also attack the battery itself. There's a health-bar on the battery, the zombies aren't allowed to destroy it.

Hurricane Upgrade Complete:
After successfully defending the battery, pick up the part from the machine. Now you can return to the Tesla Upgrade Station in the Command Center (Bunker) to build the upgraded Hurricane Tesla Gun.