1. They're masters of disguise.
2. They are always watching you.
3. They travel silently.
4. They have special technology to see in the dark.
5. They've mastered a harmless look to gain your trust.
6. They show no remorse ever.
7. They find bugs in your apartment.
8. They're too good at hiding.
9. They're combat veterans.
10. You're the one feeding them and paying for their rent.
11. They appear smarter.
12. They like to stake out the highest ground for surveillance.
13. They watch you sleep
15. They know parkour.