Some people were even left convinced they may have witnesses an alien UFO.
Videos of the bizarre sight over California yesterday were uploaded to social media and even sent to investigators at the Mutual UFO Network (MUFON) as a possible alien sighting.
The footage shows from various locations a bright point in the sky with a beam of light radiating below it.
In one video, a woman shrieked 'It's ET!', while others claimed on social media to have seen an alien craft.
But, in response, the US Navy confirmed it carried out missile tests off the coast at 3.30am and 6.20am local time yesterday.
Many people reported that they felt the missile over California was a UFO.
The Navy issued a statement saying the missiles "were not armed and did not fly over land".
It said they fired two Trident II D-5 missiles.
The statement said: "All missile test flights were conducted from sea, flew over the sea, and landed in the sea. At no time did the missiles fly over land.
"All missiles are tracked from multiple sources from launch until final impact in the ocean. The missiles were not armed."
The Navy also said they were routine tests and not in response to any "ongoing world activities".
I looked to my left and saw a bright white light with what looked like a cone shaped mist of fog.
Witness report to MUFON
But that failed to stop mounting speculation over what it was.
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US-based MUFON is the world's biggest organisation dedicated to UFO and alien research and keeps a database of global sightings.
One witness in Citrus Heights, California, wrote to MUFON: "I looked to my left and saw a bright white light with what looked like a cone shaped mist of fog.
"It then emitted a bright spotlight towards the ground. I thought it was a helicopter but as I kept looking I did not see any flashing lights.
At one point I saw a plane fly by it and could clearly see the planes flashing lights. When the object turned off its spotlight I
decided to try to catch a video of it."
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Another witness in Auburn, California, wrote: "When I really focused on it I could see a cone-shaped vapour trail emitting form
behind the object.
"The object seemed to slightly change in flight direction, it appeared to slowly drift from south to south-west and back again a few times."
Another report from Vallejo, California, included a video of a "glowing bullet-like object that left a cone-shaped cloud.
And, a fourth witness in Pebble Beach, California, who snapped it, said the object looked like "a star, then a comet, then a search helicopter, before it dissolved into space."
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