EarthBound Syndrome
A person gets so obsessed with something nobody cared about that it becomes a full-blown epidemic because of a reboot or a side reference. They swear they were born with this disease.
My friend went through EarthBound Syndrome after seeing a meme about Ness in the new Pokémon game. Now he wears a hat with the word ‘EarthBound’ and yells ‘You’re on your own, kid!’ at his dog.
My coworker got obsessed with the original MegaMan game because it showed up in a Mario Kart 8 Deluxe DLC. Now he yells ‘I am MegaMan!’ at the coffee machine.
My sister got obsessed with the old Dragon Ball Z because it came up in a new anime. Now she wears a gi and yells ‘Kamehameha!’ at me every time I leave the house.