Throw is used to throw an exception. An uncaught exception will cause the Process execution to end in an error state.
Since 5.4, if a Process has a "Subprocess to call on unhandled error" set, Throw-shapes gain the "Bypass subprocess to call on unhandled error"-option, which is enabled by default. If the process terminates in a Throw-shape with the option enabled, the Subprocess to call on unhandled error will not be executed.