Doppelgänger effect 

When you attracted to someone because they closely resemble your ex

I'm not sure if I'm into gingers now, or if it's a just the doppelgänger effect.

Doppelgänger effect by Jpinn March 29, 2016

Doppelganger effect

A causality exists in which after spending enough time with your best friend you start to dress, look, act, and eventually think the same as each other.

“Notice how those two guys sitting together on the bus have the same sunglasses, rings, haircuts, phone brand, shoes, etc. That’s the doppelganger effect. And look in the seats behind them are two girls who dress, tilt their heads and even laugh exactly like each other too”

Doppelganger effect by mogydee May 26, 2020

Dopplerganger Effect 

The effect of someone looking more and more like you as they walk towards you, and then less and less as they walk away.

I thought I saw my twin walking towards me, but I was just experiencing the Dopplerganger Effect.

Dopplerganger Effect by flanlamb January 3, 2011