Ha, I feel that. It's a fancy word but I can explain: ever seen the Avengers - End Game? When they use the infinity stones to create new timelines, they're basically creating alternate realities.

Monte Carlo simulations do exactly that: they just take your starting portfolio and simulate what happens to it in 1,000 different alternate realities. In some of those realities, the market crashes early and your portfolio goes to zero because you had to withdraw to support your lifestyle while the market was down a lot. But in other realities, the market does really well and you end up rich.