Abbreviation: BCH
Bitcoin Cash is the result of a hard fork of the Bitcoin blockchain. This resulted in the formation of a new cryptocurrency, often called BCash.
It went live in 2017, forming a new altcoin from the main chain.
BCash is a peer-to-peer electronic payment system that operates on its own decentralized node system. These miners are responsible for the validation of all transactions and ensuring there are no double spend problems.
Bitcoin Cash was further forked in 2018, resulting in Bitcoin SV. Both these had their own coins.
Controversy
Like many forks, this was the result of a dispute.
When the Bitcoin network was being upgraded, there was dispute regarding the size of the blocks. The supporters for the existing Bitcoin protocol wanted to keep the block size small, to maintain as much efficiency as possible. One the other side of the debate were those who wanted the block size to be larger, believing this would increase the number of transactions the network could handle.
Both utilize the Proof-of-Work (PoW) consensus mechanism, hence the miners are the ones who are the block producers.
In addition to increased data in each block, the goal was to lower the transaction fees on-chain. This is something that Bitcoin has battled since its start. Litecoin was designed as a faster, less expensive option and, even today, serves as an alternative to Bitcoin as a medium of exchange.
Coin Creation
Each users received an equal number of Bitcoin Cash as Bitcoin held. This is known as an airdrop. Based upon the number of coins in a wallet, the account received the same total on the new network.
This is another instance of being able to "create money out of thin air".
Unlike previous forks of Bitcoin, this one did modify the code (creating larger blocks), the first to do so.
As time passed, Bitcoin Cash ended up being a cheap replica for Bitcoin. Even with the larger block size, it did not pass BCH in terms of transactions. Also, the market cap is dwarfed by the largest cryptocurrency.