You, a wizard, have a secret wizard base. Pesky adventurers and who knows what else would simply love to find it and loot all of your precious stuff. Here are some things to consider during construction.
Remember Harold and his purple crayon?
Can you think while scared out of your wits? Lets hope your adventurers can…
In the dark alleys of Malcaresh, the Caravan City of the Plains, many an adventurer meets his death at the end of an unseen blade. Even more part unwillingly with their belongings, having fallen victim to the thieves and cutthroats plying their old and ignoble trade. Yet even among these, the whispers of House Caraguil invoke fear and discomfort.
A single room in the lair of those cast away by the gods, this place of worship is nothing the adventurers are likely to expect here.
Sometimes a painting is just a painting.
This is not one of those times.
The dread Tower of Inversion, lair of the vile lich Zarakoth Xorast, contains five layers, each containing different tools of dark magic.
In the middle of an unimportant combat with some bandits a burst of wild magic transforms all of the PCs and their opponents in to random animals and monsters. They retain their intelligence (though not, of course, the ability of speech). They can either carry on the combat in their new forms, panic, or otherwise react how they see best. After about an hour, they return, unharmed, to their normal form.