Mustrum_Ridcully
Legend
It's considerably easier to make such decisions when they are built into the game.
RC
How, exactly, does one keep a baskilisk, a boadak, or a medusa, without anyone knowing it, and without leaving any sign of its existence?![]()
It would be nice if the rules would remind you of that, especially when using random encounter tables.
But see Hussars example - when the enemy comes to you, things change a lot. If you wanted to, you could drop a Wizard memorizing Teleport and Gaze Screen together with a Medusa onto your PCs. At best you get the warning from detecting the Scrying sensor then, but would you be prepared for a Medusa?
And there is nothing in the rules forbidding it, nor is it entirely unreasonable to assume that such a thing could happen. Especially the enemy going after the PCs is something that one would expect to occur from a verisimilitude* point of view.
*) Hey, long time, no see, verisimilitude! And even typed correctly on the first attempt!