A doppelgänger.... literally "double-goer" is a non-biologically related look-alike or double of a living person, sometimes portrayed as a ghostly or paranormal phenomenon and usually seen as a harbinger of bad luck. Other traditions and stories equate a doppelgänger with an evil twin. In modern times, the term twin stranger is occasionally used.[1] The word "doppelgänger" is often used in a more general and neutral sense, and in slang, to describe any person who physically resembles another person.

In real life
Izaak Walton claimed that English metaphysical poet John Donne saw his wife's doppelgänger in 1617 in Paris, on the same night as the stillbirth of their daughter.

German playwright Goethe described an experience in his autobiography Dichtung und Wahrheit in which he and his double passed one another on horseback.

With the advent of social media, there have been several reported cases of people finding their "twin stranger" online, a modern term for a doppelgänger. Twinstrangers.net is a website where users can upload a photo of themselves and facial recognition software attempts to match them with another user of like appearance. The site reports that it has found numerous living doppelgängers—including three living doppelgängers of its founder Niamh Geaney.

Do you believe in doppelgangers?

I think it's quite probable that the gene pool throws up near identical genetic configurarions at times. so on that level, yes..
As for the ghostlike paranormal aspect, My only experience is in dreams.
Btw if you see some frantic bloke in a dream one night coming out of a supermarket, totally starkers, clutching a dwindeling box of cornflakes, and persued by pidgins. It was probably me.

Lol.

When I was as about sixteen, I was walking through my home town when I saw someone coming towards me who seemed oddly familiar. As they got closer, it became clear that this person was myself. As we passed, I/they smirked at me in a knowing way. When I looked back, they had disappeared. Needless to say, this scared the chit out of me but even my closest friends listened to my tale with, shall we say, polite scepticism.

I pity the fool who looks like me.

I have encountered two of them.

Yes I do because I met mine when I was a teenager. What an experience seeing yourself without the use of a mirror.

good

Good what?

Hi

Hi back

Truthfully?

I thought they make molds of you for every garden...

In Alf or David form?

I have often laughed at what would befall the dumb*** who stole my identity!

Traveling all over the world I have seen many people who are the spitting image of someone I knew from somewhere else, even some family members at times. It sometimes seems freaky but it now happens so often that I almost expect it. Sometimes even see people that look like prominent, known actors. Recently even two on the same train in Europe. Whenever I can I take a quick snapshot, to compare.
The weird thing was when an upcoming actress appeared in Hollywood movies several years ago that looked very similar to my ex-wife (back when we were still married). Especially in certain movies or pictures when the actress was made up a certain way. To test this I put a picture of her and one of the actress' pic next to each other and showed them to people in my family who knew her well, they sometimes did not pick out the right one.

Quite interesting responses. I never really believed in doppelgangers until someone messaged me a few days ago who is a spitting image of my husband who died almost one year ago. I am still unsure if it is a Scammer using his photo...But it is very unnerving to see him also turn up on the forums.
It is ghostly....

Yes and it was one of the strangest things you can imagine but I'd more or less forgotten it until your thread reminded me about it. No idea what it was but at least I don't seem to be alone in having this experience .

Well a bit like me

Never encountered my own but I've seen others.

I did meet a person who seemed to have an exact matching personality of someone else I knew at a younger time in a different part of the country.