The powerful new Wonder Weapon, the M.A.D. (Modular Atomic Disintegrator) can be upgraded in Attack of the Radioactive Thing!. Here’s how to do it.

Every Zombies map includes a massive Easter egg, but you’ll also finds tons of shorter quests that provide big pay-off rewards for discovering their secrets. One of those rewards is an upgraded M.A.D. — turning an already powerful anti-Zombie weapon into an invaluable tool for high rounds.

Here’s how to mutually assure some Zombies destruction. Check out the step-by-step guide for upgrading the M.A.D. below.

More Attack of the Radioactive Thing! Zombies guides on The Escapist:

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• Zombies: Attack of the Radioactive Thing – How To Turn On Power
• Zombies: Attack of the Radioactive Thing – How To Unlock the Pack-A-Punch
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How To Upgrade The M.A.D. Wonder Weapon

The first step is acquiring the M.A.D. itself. The Wonder Weapon, like most Wonder Weapons, is only available from the Magic Wheel. Check the sky for a bright light to find the Magic Wheel’s random spawn location, then spend points on random rolls until you (hopefully) get your hands on it.

Once the M.A.D. is in your hands, here’s what you’ll need to do to upgrade it.

• #1. With the M.A.D., unlock the path to the Motel and look in the storage closet behind Bomb-Stoppers, up the steps from the pool. Collect the Crowbar item here.
• #2. The Crowbar is a melee weapon you can use to unlock specific boxes located in three locations around the map. There are three parts you’ll need to collect.
• M.A.D. Part #1 (Grip): The first M.A.D. part is in a grey wall-mounted electric box outside the Public Restroom Men’s Entrance in the trailer park / camping ground area.
• M.A.D. Part #2 (Plunger): The second electric box is behind the buildings on the main street near Spawn. Go to the street and find the path that leads down to the Beach behind the Gas Station. In the back alley, look on the far-left corner wall, near the dumpster (and a framed picture of your captor).
• M.A.D. Part #3 (Crank): The last M.A.D. part is on the exterior of the TV Station where Elvira resides. It’s on the wall facing the parking lot, where one of the random blue portals appears if you’re attempting to unlock the Pack-a-Punch.
• #3. Now the M.A.D. is fully upgraded. Each upgrade appears on the M.A.D. and adds some extra functionality, so you don’t need all three parts to actually upgrade. Each part is like an individual, tiny upgrade — but you’ll get the achievement / trophy for getting all three.

With all the parts, your M.A.D. isn’t just stronger, it’s more useful. You can suck up radioactive goo from the green mutant blobs scattered around the map, and you can charge the Wonder Weapon by holding ADS (Aim Down Sights) and turning the crank.

The cranked M.A.D. can blow away entire groups of zombies with one shot. You can reload it too. That makes it a very functional Wonder Weapon.