what if people around me started behaving strangely one by one theme

We imagine what it would be like if more or less everyone around us started to act in an unusual way for no obvious reason.

Examples

In ds91x18 "Dramatis Personae", people around Odo started to act out of character, acting clandestinely and inquiring about his loyalties. It turned out an alien transmission was turning them into two opposing factions.

19 total · 5 choice · 13 major · 1 minor

StoryLevelMotivation
ds91x18 choice The space station crew's minds taken over by telepathic archive from Odo's point of view.
ds92x14 choice people were weird from replicat Miles' point of view
ent2x09 choice Everyone around T'Pol became strangely obsessed with the particular tasks they were working on.
movie: Disturbing Behavior (1998) choice The high school senior Steve Clark and his close friends watched as the students at their school turned into perfect goody two-shoes students one by one and worried that the same fate awaited them.
pkded1x07 choice The local kids were perplexed as adults started acting oddly. It became apparent that adults were being replaced with alien facsimiles.
movie: Body Snatchers (1993) major The people around Marti were getting replaced with utterly emotionless replicas, one by one.
movie: I Married a Monster from Outer Space (1958) major The men of the town in which the film was set became occupied by aliens one by one.
movie: Invaders from Mars (1953) major Everyone around David became mind controlled by Martians one by one.
movie: Invaders from Mars (1986) major Everyone around David became co-opted by Martians one by one.
movie: Invasion of the Body Snatchers (1956) major Miles Bennell and Becky Driscoll notice the people of Santa Mira turning strange one by one.