That is typically referred to as an "invisible" entity or object. It is something that exists in reality but cannot be perceived by the human eye.
Answer:
impalpable
There is no proof that aliens exist. I believe there is no such thing as aliens. Has anyone seen an alien ship? Has anyone seen an alien? No.
delta
married, how are you, your name again, kids, what do you do
Well a Kraken is a mythological creature, so there never was a first sighting of something that didn't exist. But it was seen in Pirate's of the Caribbean ;)
Actualization is the concept of making something existent in reality.
Well.... you can't really prove something doesn't exist, you can only prove it does. But, nobody has found or seen a pikmin outside the game.
presidents in god we trust date denomination
Unreal means something that doesn't exist, cannot be heard,smelled,tasted,felt, or seen. Something Unreal, is simply fake.
Because he doesn't exist.
Yes. they exist but rarely seen same as the deadly serpent an nightmare.
A coal hewer is another name for a coal miner. It is a name that is given to the men often seen with coal dust and ash on their faces.
No. Use "you saw something" or "you have seen something," depending on context