If you mistype an address (such as with a typing error) and you are using the Bitcoin Core daemon to create the transaction, then the daemon will recognize that the checksum which is built into the address does not match the rest of the address value. It will therefore tell you that you have provided an invalid address and it will refuse to send the transaction.
If you put in an address such that the checksum matches the rest of the address data (such as if you enter an actual address, but not the address that you intended), then the daemon will build the transaction you requested and will broadcast that transaction for you. If you obtained that address from someone other than your intended recipient, then the person that you obtained the address from will receive the bitcoins (instead of your intended recipient).
If you hashed random data (instead of a public key) and then added a matching checksum, you will have created a valid address for which nobody has the necessary private key. The daemon won't know that nobody has the private key, and since you intentionally created an address with a valid checksum it will allow you to create and broadcast the transaction. The funds will then be permanently locked at that address and will never again be able to be spent by anyone.
Please post your altcoin questions in the altcoin forum:
https://bitcointalk.org/index.php?board=67.0
There are thousands of altcoins, and they each have their own codebase with their own features and behaviors.