Summoning stone

Summoning stones are a type of consumable used to summon allies. The ally will be at the player's level and last for 30 minutes (with one exception) or until slain in combat. Activating a summoning stone causes the player to suffer from Summoning Sickness, preventing them from using another summoning stone for 10 minutes. Each summoning stone can be used only once (with the same exception).

Summoning stones can only be used in explorable areas and there can only be one summoned ally in an instance at a time. This ally will follow the summoner, similarly to minions or other combat NPCs, but they almost never break off combat, often leading to their demise in the event of a retreat.

Trivia

 * Summoning stones were first added to the game in the Thursday, September 4, 2008 update. "The Igneous Summoning Stone [was introduced] to help players level up new characters so it can only be used by characters under level 20." (Official ANet announcement)