can some one explain my conception that only one person has to show there cards at the showdown, and if no one can beat that guy, the losers don't have to show?

IS THAT A REAL THING?

what's that called?

It's called mucking.

i call your bet lets see what you have... your a fish

so if there are 4 callers after the river, all four have to show right?

Not if they don't think they have the best hand. Only the winner HAS to show, though a player can ask to see the losing hands and I believe a lot of casinos will let you.

^ A player can sometimes request the dealer to show all hands, and the request may be honored (at the dealer, staff, or TD's discretion) at some tables. Otherwise a losing player should never be required to reveal their hands. I would avoid card rooms that have explicit rules otherwise.

In any game, once a players cards touch the muck pile they are dead. D-E-D Dead. Period. No player or dealer should ever touch or remove cards once they're put in the muck. If it happens, get up and complain to the floor manager or TD immediately.

On the flip side of that, management can remove identifiable hands from the muck, but the circumstances for it are fairly uncommon. (Dealer mucking a protected hand, a player fouling another player's hand, and the dealer failing to declare a shown winner)

Not sure why you flipped on a mucked hand. A hand that touches the muck or thrown in the muck is not always dead, contrary to public belief.

I've never seen it happen, but that's actually the only case I've ever heard of cards being removed from the muck, with the exception of shuffling it back in to continue some draw games. What happened, supposedly, was someone caught trip aces, and the winner showed jacks, both players thought he was on trip jacks and the dealer failed to declare jacks full before awarding the pot -- nobody realized it happened until the next hand was already dealt (the pot was awarded to the jacks full on dispute -- cards speak -- though there's possibly an argument that the mis-declaration fouls, I don't think anybody would realistically be fouled for under declaring). The key part of this being the cards-speak rule and the winning hand being shown before the pot was awarded and cards were scooped.