👽 Alien NPC Infiltration Challenge

Hello everyone!
Following the new discoveries from April Black on how NPCs work, I present to you this silly little challenge where your alien sim infiltrates society by replacing its Service NPCs. 🌌

🛠️ Requirements

Essential:

• boolprop testingcheatsenabled t to access CAS debug mode and create alien sims.
• SimPE to manually turn sims into Service NPCs.

Optional mods:

• No Townie Regen, Anti-Redundancy, There Can Only Be One Professor – to control NPC spawning.
• Female Alien Impregnation – if you want females to get abducted.
• Dina’s Residential Care – to facilitate meeting NPCs.

🌠 Story Background

You play as an accomplished alien technician finally ready to settle down.
But before retirement, your superiors assign you one final mission:

Infiltrate Sim society by replacing every Service NPC with alien offspring.
These NPCs perform key roles in Sim life – and your superiors want undercover agents in every one of them.

📋 Challenge Setup

👤 Main Sim Setup

• Create a young adult alien in CAS (any gender). You can start with an adult/elder in the main hood, but you must reach university eventually.
• Start on an empty lot (no pre-built house).
• If at university, do not live in a dorm – privacy is essential for alien experiments.
• The challenge fails if your main alien dies. If necessary, you can also use Elixir of life just for them.

🏠 Lot Rules

• Begin with an empty lot and build your home gradually.
• Once your household grows and the building is large enough, you may rezone it into an apartment.
• If you're in an apartment, you may move NPCs and their children into separate units on the same lot, but play them rotationally.

🔬 Breeding Protocol

• Your goal is to have one alien child with each Service NPC category.
• Only one child per job is needed (e.g., if you have 3 maids, you just need one alien maid-to-be).
• That child must eventually take over the role, disposing of all others.

If normal conception is not possible:

• Use a Breeder Alien (of compatible sex) to impregnate the NPC. (more on breeder aliens later).
• If still impossible, simulate an alien abduction pregnancy using a telescope.
• NPCs who give birth due to abduction must die after childbirth (being abducted and delivering proves to be too much trauma). A replacement NPC (same job) should help raise the child.

👶 Baby Rules

• Babies must have green skin. If not, they must be disposed of (killed off at the first opportunity).
• Babies must match the gender required by their future NPC role (e.g., headmasters must be male).
• If the baby is the wrong gender:
  • You may keep them as future breeders (this is useful to have babies with sims of the same sex of your founder).
  • If a child is not eligible to replace their parent as a service NPC, you can try again until you have a child that fits all the criteria needed.
• Children may attend university only if:
  • They wish to do so.
  • It doesn't prevent fulfilling their role.
• Once a child is old enough:
  • The NPC parent must be eliminated.
  • The child becomes the new Service NPC in that role.

🧍 Service NPC Rules and Checklist

• Only safe NPCs are included (no repo-men, social workers, etc.).
• You may ask NPCs to move in once you're friends.
• Reproduction must happen as soon as possible after moving in.
• NPCs should assist in raising the child so they learn the role.
• In university, you may graduate before attempting reproduction.
• Some Service NPCs are teenagers. One of your alien children must befriend them, and they should move to university together. Once there, either your child or your main alien sim (if appropriate) must reproduce with the now young adult NPC as soon as possible. The resulting child must always be raised by your original alien and the Service NPC parent, even if your main sim is the grandparent of the new baby.
• Some service NPCs can be only elder females. The only way those sims can biologically reproduce is by becoming plantsims and create a plant-baby. Raise the plant-baby and have them breed with either your main sim or a breeder. Once an alien female is born, dispose of the plant-baby.

If you want a checklist of all the service NPCs you must replace, i will leave a list here:



If you decide to attempt this challenge, let me know hot it turns out for you and if you'd change some of the rules. Have fun!

Wouldn't it be better to just use this mod and replace all service NPC-s from the beginning in a new hood? https://www.patreon.com/posts/ts2-sim-bin-npcs-76201881 But I guess not for this challenge... It would be too much work for me to do a challenge in SimPE ; ) but it's an interesting idea if it comes to the concept!