Interact is an Expect command which "[g]ives control of the current process to the user, so that keystrokes are sent to the current process, and the stdout and stderr of the current process are returned." [L1 ]
Interact is quite amazing. [Elaborate]
While there is Expect for languages other than Tcl, in the sense that a few other languages have extensions that (partially) manage ptys and demand-response dialogues, I know of no other that offers interact's functionality. On the other hand, interact is part of the evidence that most programmers don't know what Expect can do for them; only a tiny minority of Expect scripts appear to invoke interact.