Simulacrum Item Duplication
This is clearly a broken spell if used to its true potential: Equipped items the caster has can be used by the simulacrum without using up the original items. Also, the game does not check the number of summoned creatures when the simulacrum is doing the summoning. The possibilities are endless but here are a few suggestions:

Weapons:
Staff of the Magi: 3xFireball-Lightning (plus it's about the best weapon for a mage to carry)

Staff of Fire: 20xLesser Fire Elemental (simulacrum runs out of time before running out of charges). Since the simulacrum bypasses the 5 creature limit this can create a real swarm of elementals. Earth or air would work as well, but I like fire since they live happily in Incendiary Clouds.

Quick Items:
Current Inventory: 2x Prot Magic, 2x Time Stop, 2x Incendiary Cloud

Protection from Magic scrolls: There are only 2 of these (that I know of) in the game, probably because total magic invulnerability is so powerful. The simulacrum can use both every time it appears without damaging the originals. There is a small drawback in that it includes protective and healing magic. The shielded character can still heal (slowly) with regeneration items.

Level 9 spell scrolls: This is the solution to not being able to reach a high enough level to cast them. I like Meteor Swarm, Time Stop, Wail of the Banshee, and Spell Strike. Gate has potential though.

Level 7/8 spell scrolls: These aren't as powerful as the level 9 spells, but it's easier to get multiples of them. In particular I'm looking at abusing the no maximum creature limit with stacks of djinni and efreeti scrolls.

Wand of Wonder (lots of fun, if not the most effective)

Rod of Resurrection

Other items: Necklace of Missiles, Gloves of Healing, Ring of Energy, Ring of the Ram - adding most of these is overkill, the simulacrum can only do so much in it's short life.

Submitted By: Nighthawk

Simulacrum Tactics
We all agree that simulacrum is a very good spell. But you can cast it even at the early chapters by getting Vhailor's Helm. Of course straight mages can't use it however the rules for simulacrum still applies, you can equip the simulacrum with items requiring charges etc. and use protection scrolls (specifically protection from magic).

With the helm, you can get your best fighter a doppelganger at half his level. This doppelganger can imbibe enhancing potions to make them more effective. You can call upon 2 efreetis with bottle of efreeti or you can summon 2 Ras swords to help you fight (straight mages can't even equip this sword so it's like getting 2 inferior Mordenkainen's sword early in the game).

The protected from magic characters make mincemeat out of liches, mages, mephits, beholders and other magic dependent enemies in the game (they have lousy meelee abilities). And you can recycle the protection from magic scrolls over and over and over. I would not advise using this tactic against meelee tough characters as the fighters are better off using strength enhancing potions themselves or when facing enemies that can impart status effects with their hits (shadow fiends hold and vampire level drain come to mind) but the temple sewer gang were pretty easy with two tough fighters protected from magic distracting them while my casters wrecked havoc on the group as their mage and cleric wasted their time on the fighters as well. It is also advisable to send a tough character in to deal with summoned pit fiend etc.

But with this tactic, you can take out the Athkatla liches, Kangaxx and the twisted rune as early as you would like providing you have the right weapons to deal with them.

Submitted By: Jeremiah