Bernard the Alien will randomly spawn somewhere in the house. To unlock this achievement, you must find and interact (by pressing

) with Bernard. Doing so will warp Bernard back to the planet Ceiphe. You must be quick once you get close as Bernard will make a run for it and disappear.
This is best done between chapters.
I unlocked this achievement after completing the “Rakan” chapter and still having the “Lucy” and “Dolores” chapters to go.There are 4 confirmed locations throughout the house where Bernard can spawn. These locations can be seen below:*
Location 1 - Living room near the front door.
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Location 2 - Living room #2 on the way to the progress room.
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Location 3 - In the basement on the way to the storage room with the freezer and the electrical room.
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Location 4 - In the garage. The garage can be accessed by collecting the note on the garage door, finding the garage key inside the dryer in the laundry room (take a right after entering the kitchen, then another right to find the laundry room) and using the garage key on the garage door to unlock it.
You can go to a spawn location above, make a manual save and then keep loading the save until Bernard the Alien spawns at the location you are at (or check all four locations above then reload).