Alien Parts are parts in Bad Piggies that are very unique and special. The sounds for almost all of the alien parts are different. All alien parts are gained after unlocking all of the normal parts in the game, easter egg parts are not included. Unlike most of the other parts, they all have an extra feature or boost. There are 15 in total.
- The Alien Variation of the Pig floats down slowly, as if in low gravity. However, when in a frame, it'll float upwards quickly, so larger vehicles will fall slowly.
- The Alien Variation to an Egg applies blue slime in between all blocks in a vehicle if used. The slime looks and functions identically to the glue powerup, except colored differently.
- The Alien Variations to both Soda Bottles now do different things. The green soda bottle has extremely strong force, while the black one has its color changed to blue and the thrust is now infinite.
- The Alien Variation to the Electric Motor is the most powerful motor in the game, more than twice as powerful as the V8 Engine. Due to its high speed, it is prone to launching vehicles extremely far. The extreme acceleration can sometimes even break apart the vehicle.
- The Alien Variation to the Propeller functions the same, but pushes vehicles in the opposite direction, similarly to a Fan.
- The Alien Variation to the Helicopter Rotors go in reverse, similar to the propeller.
- The Alien Variation to the Metal Box is extremely slippery, functioning similar to ice ground.
- The Alien Variation to the Grappling Hook shoots an explosive lightning bolt. The range of this is higher than the normal version. The bolt will explode after hitting the ground, any player-made object, any naturally-spawning object, a star box or cake, or after reaching its maximum range. Note that the lightning bolt itself can pick up Cake Race cakes and star boxes, but not the explosion. If an explosion happens near enough to it, it can make the bolt go at an angle, or make it go even faster.
- The Alien Variation to TNT causes an explosion of the same size as its normal counterpart, but can explode infinite times. It is also not triggered by force. Instead of "TNT" written on it, it has strange glyphs. It doesn't work in dark levels, where it can only detonate once.
- The Alien Variation to the Lamp Light makes all the dark areas illuminated, similarly to the Night-Vision Goggles powerup. If it is the featured part in cake race and/or is used in a non-dark level, it doesn't have the green effect.
- The Alien Variation to the Boxing Glove has double the Punching Power and Range. It is also notable that the glove at the end looks similar to the tentacles on the alien pig.
- The Alien Variation to the Tiny Wheel makes it powerable, acting similarly to the powered Wheel. It isn't faster, though, and weighs the same as a powered wheel.
- The Alien Variation to the Fan gives even more force than a propeller.
- The alien variation to the Bellows gives more force than normal.
The Alien Parts all emit small green or blue particles. They can also appear on the title screen, functioning the same. When an alien part is collected from the machine, a different sound effect is heard. A similar sound will also be heard when equipping one. When the final normal part is collected, it will play the alien part collected sound. This is likely a signal that the part collected was the last of the normal parts, rather than a bug. The Scrap Machine will undergo a transformation and then only accept 3000 scrap to unlock 1 alien part. Unlike its previous version, the machine will also show the silhouette of the next part that will be obtained. This can't be changed or chosen. They can't be obtained from crates.
In the current loading screen, among other new parts, the alien engine can be seen flying, attached to a normal propeller. In previous versions, it was a normal electric engine. There is a video of this down below:
- A green box with the art style of the alien parts appears in the game files. It doesn't appear in-game, but it may have been intended to be an alien variant for wood at some point. It probably wouldn't have low friction like the ice block, and it appears more like a window.
- The pulse sound effect played by the engine is similar to a heartbeat, like the pulse texture on the item.
- The symbols on the alien TNT appear written on stones in The Road to El Porkado.
- When the alien pig is equipped, it plays the normal sound and one of Ross' sound effects, but distorted. When used, the pig sounds the same, though. It might have been the alien pig's intended voice but it was cut short due to time.
- The Alien variant of the Electric Engine used to be an epic contraption (3-star)
- If you attach a normal helicopter rotor powered by the alien engine to wood, it will instantly snap off.