How do you explain Martingale to someone who doesn't understand EV?

[AlmightyJay]

I'm having an argument with some people who claim that Martingale works, in theory, if you have an infinite bankroll. I'm trying to explain to them that because each bet has -EV, it doesn't matter how much money you have, you're still doomed to failure. (I'm correct, right? They have me doubting myself)

However, they're clueless about what EV means, so I can't argue this way. How do I explain why it doesn't work without using EV?