However it looks like Messages isn’t the only messenger client to be affected by such a bug. Recently it has been discovered that a similar bug is affecting Skype as well in which sending these characters (without the quotes) “http://:” will cause the app to crash/hang. In fact once the message is in your chat history it basically prevents the app from reopening again.
This was initially posted by Skype user on the app’s forums with the folks at VentureBeat testing it out for themselves and finding that it is true. According to the user Giperion who posted the issue, “Clearing chat history not helps, because when skype download chat history from server, it will crash again.”
This seems to affect Skype running on Windows, as well as the mobile versions for iOS and Android, but oddly enough the Mac version of Skype seems to be unaffected. For Windows users, there is a solution in which it will have to rely on the person who sent you the message to delete it, as pointed out by Skype user Lazymax. Alternatively you could downgrade to version 6.x which seems to resolve it, but unfortunately that is only an option for desktop users and not mobile.