Insert Raw Expression...
Insert Raw Expression gives you a dialog box for pasting a Mathematica InputForm expression directly into your notebook.
This command is intended for advanced users, who are familiar with the expression syntax of elements in Mathematica. The text entered in this dialog must be the correct underlying expression representing the desired element.
Keyboard shortcuts: * or 8 (Windows); * or 8 (Macintosh); * or 8 (X).
See The Mathematica Book: Section 2.11.1.