|# of attacks||1|
|Wand cancels||polymorphing items|
Wearing a silver mantle deflects all magicians' morphs. Firing a wand of cancellation prevents zapped magicians from using the ability.
A magician can turn worthless items in your pack into valuable ones. First, drop all non-worn items which you do not want him to change (the magician's spell cannot affect items you are wearing). The magician's spell doesn't affect quest items. When your pack quivers, a transformation has taken place. Check your pack, dropping the new item if you wish to keep it. Once the magician has changed all of the items that you wish him to, do not kill him. Leave the level, noting down his location. Then, come back with more items later. Keep all the worthless items you can carry.
Like many monsters, the abilities activate when the creature itself is hostile. While the summoned monsters are a bit more than a headache, the item-transforming effect can become like bargaining in a bazaar that is practically limitless compared to the one already in the game. The summoning effect is instant (the message bar says absolutely nothing in this regard). If the magician were to be backed into a corner, the summoned magic users can appear beyond the walls into nearby rooms and corridors. If you've become faster, zap him once with a wand of hastening so as not to waste too much time.
If you stumble upon a magician early in the game, have him replace one of your scrolls with transport.
Keep in mind that a magician's transformations cannot alter an item's class. Potions, for example, can only be morphed into other potions(potions cannot be turned into alchemy potions) and cannot be made into, say, empty vials(a scroll of wonder might do that instead).
With clever tactics and patience, one can make full use of an Archmage's presence by having him eliminate all worthless items from the game - one at a time - eventually leaving only the best items available throughout both the Magician's possible transformations and the remainder of the game.