To control the monk in the MS-DOS version, press Ctrl-F3. Control him using: T, Y, U, G, H, J; B, N, M. Press Tab to use him.
Click on the upper left corner of the main menu, and type "CTHULU" (for v1.2), or "YOG" (for v1.3). Control him with the above keys. NOTE: This code is for the diskette version. It doesn't work on the CD-ROM version.