SMS Spoof allows you to send an SMS message to someone and change who it's from (the Sender) and also receive sms messages from any number. For example, you could send a message to someone and make the sender "Ex Girlfriend" and set the message body to "I'm Pregnant!!" In the images below, there's an example of how that will look on the recipient phone.
Currently SMSSpoof only supports the Twilio SMS API. In the future there will be support for other SMS API's such as MessageBird, Sinch, Nexmo, etc...