You may have tried to use the following 'cheat':
"Find a dragon and cast a 'MON ZO GOR SAR' spell then press 'ESCAPE' to pause the game. Now whilst holding down the left 'ALT' key type in: 'LORD LIBRASULUS SMITES THEE DOWN' (with spaces). Unpause the game and kill the creature, now when the dragon dies it should leave behind a Firestaff and the party should also be invincible."
Unfortunately, it only just pure invention. This was originally published in ST Action magazine (UK) as an April Fools joke written by Nick Clarkson who was the editor of the magazine. Many other magazines and web sites reproduced it without actually checking that it worked. Below are some examples.
[Source: Abandonware Magazines]
Note that in this example, the cheat wasn't even spelled correctly!
[Supplied by Adamo, Source: Amiga Magazine Rack]