(The smell of oleic acid is what ants use to recognize a dead ant. By dabbing a living ant with oleic acid, it'll believe that it's dead. Other ants will then try to carry it to the ant graveyard and the affected ant will just accept its fate because it thinks, "Well darn, I'm dead, take me to the graveyard.")
A man by the name of Costantin Reliu was pronounced dead after he went missing.
He ran away to Romania and left his wife and daughter behind. He cut off all contact, so his wife assumed that he died in an earthquake that took place a while back. Eventually she eventually wanted to remarry (after 14 years). To do so, she needed to first divorce her current husband, which isn't exactly possible if he isn't there. So she filed for his death certificate. This was approved.
He was eventually found with expired residence papers and deported. It was only upon returning did he find out that he was dead.
Of course he went appeal this and it should have been quite easy. Just showing up should be enough evidence to prove that you're not dead. However that's not the case in most countries.
In most countries, a declaration of death can not be reversed after a certain number of years have passed. With his appeal declined, he didn't own a social security number. Without a social security number, he couldn't apply for a work permit and he also wasn't able to apply for social benefits. --> No income whatsoever
Doctors wouldn't even treat him doctors due his missing documents, which was an issue due to his diabetes.
After his story went viral, he still wasn't able to directly reenter the world of the living. After multiple months it eventually worked out.
Moral of the story, don't go missing for years unless you've already prepared a new identity with paperwork.