They have a magenta color and travel towards the gem with the highest raw maximum damage that is in a tower or amplifier. (If two gems are tied for the highest raw maximum damage, the specter will pick whichever is first in the game's internal gem list.) They always leave a battlefield with a gem. Any remaining specters need to be killed in order to complete the field.
Specters' health grows with the monsters', reaching enormous amounts in later levels.
They award EXP, Shadow Cores, and Mana upon kill.
If it appears early in a battle, it's best to restart it.
They can be "juggled" by changing the location of the most valuable gem on the field. The specter will move back and forth between the two locations, making it an easy prey for the defenses.
They can also be killed with gem bombs and shrines. Additionally, they can be frozen using the freeze spell. Using it with a gem enchantment spell can kill them quickly.
The following achievements are related to specters:
- Don't Touch my Gems!: Kill a specter.
- Gem Lust: Kill two specters in one battle.
- I Told You... (GC2) / I Warned You... (GCFW): Kill a specter that carries a gem.
- Not So Fast: Freeze a specter.
- Multikill: Kill a shadow, spire and a specter in a battle.
- Specters have the same max mana limit as Apparitions (99999).
- If a gem can't be stolen, it will fly from one side of the field to another, instead of leaving completely.