Let's say McDonalds issued their own tokens on a block chain, called BigMacBux. You can redeem 100 BMB for 1 bigmac. People buy and use these bucks as currency. Someone wants to open a new burger chain called WcDonalds and want immediate customer base, so they tell the world "Hey World! If you had any BMB today, you automatically have the same number of BigWacBux on our blockchain. Come and redeem your BWB today!". So people do that. They take their free BWB, get a free burger and then forget completely about WcDonalds. WcDonalds will still create burgers and sell BWB, but you can't go at McDonalds and pay with them. They are separate entities with different tokens, but with a shared history.
Close,... BurgerKing in Russia issued the Whoppercoin back in August.
http://fortune.com/2017/08/25/burger-king-russia-cryptocurrency-whoppercoin/