Plague Inc. Santa's Little Helper Scenario: Mega-Brutal 3 Biohazard Guide

Take a break from mass-murdering the world and spread happiness instead. That is what the "Santa's Little Helper" scenario is all about. The Neurax worm is here to help the fun-free world and will help spread love, happiness, and joy to everyone in this anti-fun version of Earth.

Not only is this scenario a change of scenery, but is also quite simple and easy--even on mega-brutal. My strategy here won't be as complicated as the other scenario guides I've written in the past.

Although this scenario is basically just the Neurax Worm, you will have a very different set of transmissions, abilities, and symptoms. All of which concern Christmas-y and holiday spirit-y names & descriptions, there are also naughty symptoms(They're black). You will also be starting in a world where no airports or harbors are open, don't worry they'll be open at some point as long as you evolve the necessary symptoms.

Needless to say, we're going to aim for 3 biohazards in mega-brutal difficulty for this scenario which also lets us unlock the "Complete Santa's Little Helper" achievement.

I could write more boring and useless stuff, but no, now let's get to it.

Difficulty: Mega-Brutal
Recommended Genes:

  • ATP Boost
  • Aerocyte - Aquacyte is also an option. Actually it just might work better, but I chose this instead because I'm starting in Saudi Arabia.
  • Trans-Stasis
  • Genetic Mimic
  • Extremophile

This strategy will not make use of the Trojan Planes available to Neurax Worm. Instead, we'll let the worm infect countries on its own without the help of planes. 

1.) Start your plague in Saudi Arabia. Then immediately evolve the following in this order:
  • Cracker Cocoon
  • Emotive Radar
  • Santa's Little Neurax Worm
  • Festive Tendrils
  • Digital Elf
  • Digital Herald
  • Digital Angel

2.) During this step, the world will probably start opening their point-of-entries again. That being said, continue by evolving the following in this order: 
You can actually experiment with this part, there is no order which ensures 100% win-rate every time. I just like to use this order to maximize my infection rates leading to the cold island countries.
  • Solar Perfume 1
  • Solar Perfume 2
  • Eggs-Nog
  • Sunny Side Up
  • Snowballs 1
  • Snowballs 2
  • Fair-Weather Friend
  • Glow Worms
  • Snow Worm
  • Wellington Worm
  • Wild Side
  • Stocking Filler
  • Radio Worm
  • Gold Digger
  • Memory Lane
If you notice, we just evolve every single transmission. Guess I should have just wrote that instead, huh? 

3.) Now we just have to evolve some symptoms, and an ability, that'll improve our worm's infectivity. Evolve the following in this order--don't worry we're not evolving everything again:
  • Laughter
  • Excitement
  • Joy
  • Indulgence
  • Partying
  • Genetic Reshuffle 1
Why Genetic Reshuffle? To boost our score even more, of course. If you think you won't need it, evolve what you want, it's your game, bro.

In the end, our transmission, symptom, and abilities tree will look like this:

Experiment with this strategy all you want, this scenario isn't like Black Death that's complicated in every way possible. God, I hate that scenario.

There you have it, All praise the worm! Here's the scores I had on the last 3 games I played.

Again, Complete Santa's Little Helper achievement if you're able to finish this scenario with 3 biohazards. You could also do it on lower difficulties, but where's the fun in that?

I'm sorry if the images are warped, my internet connection has been acting up lately and causes some weird things to happen to everything I upload. I have reason to believe it hates me more than it did before.

Thanks for reading this guide and I hope it helped you get those 3 golden biohazards, and as always, Happy Spicy Gaming!


  1. Really good guide- 352 days and 31% cure progress

  2. So... got to Evolving "Partying" when the world was fully infected. Game over BUT: Completed at 369 Days, 30% cure completion and a score of 66,821 for 3 Biohazards!

  3. Ok- so... It worked… but not entirely. I beat it on mega brutal- but only got 2 biohazards... By the time the whole world was infected, I still hadnt gotten all the transmission traits...

  4. I followed the guide exactly and finished in 333 days, the cure was 20% complete, and I got 76,058 points for the three biohazards. Great guide!

  5. i didn't evolve any of the symptoms in part 3 but instead i took genetic hardening 1 and 2. i also took contentedness, appreciation and harmony. ended up with 22% cure and 3 biohazard. took me 343 days

  6. 1st game, 3 biohazards, 77,057, 326, 23%. Followed the guide to a T... Great guide.

  7. Ariel Iván AguayoJuly 25, 2015 at 2:57 AM

    First game, three biohazards! =D At the part with the transmissions, I did whatever I felt was appropriate for infecting the countries I wanted (hot counties, rich countries, etc). At the end, I used a genetic reshuffle 1 instead of partying, because I had only one country left. c: