Conjure Phantasm

Acquisition
Skill Quests: Skill Trainers who will teach this skill before it is unlocked:
 * A Mesmer's Burden (Lakeside County)
 * Mesmerizing the Enemy (Sardelac Sanitarium)
 * Locate Mei Ling (Sunqua Vale)
 * Sir Bertran (Ascalon City)
 * Dakk (Ember Light Camp)
 * Zytka (House zu Heltzer)

Usage Notes
A simple and effective skill, Conjure Phantasm will worry any enemy you cast it on. What is especially nice is that it essentially ignores armor -- that is to say, since it doesn't actually deal damage directly and instead gives health degeneration it will deal the same amount of damage to any given target regardless of armor.

Conjure Phantasm has a moderate cost and quick recharge, so if desired you can keep it active on an enemy indefinately.

In PvP it can be useful for general purpose damage on the primary target when you have spare energy. It can also be used on any member of the other team to force their Monk to spread his healing around.

Use Conjure Phantasm on fleeing enemies who are badly injured to punish them for straying from the healing range of a Monk. Conjure Phantasm will be most effective on players who do not have powerful self-heals.

In PvE it's pretty much the same -- use this skill as a general purpose damage dealer when you are waiting for better skills like Backfire or Empathy to recharge.

In Pre-Searing Ascalon, Illusion should be your main attribute line because of Conjure Phantasm. If you do it correctly, melee attackers should be near-death or at half life before they reach you when you cast Conjure Phantasm plus Imagined Burden.

The -5 health degen is equal to 10 hp lost per second, making the total damage dealt by this skill a simple 10 x duration.