Encounter ✦ arcane, cold, implement, teleportation
Target: 1 or two creatures
Attack: Constitution vs. reflex
Hit: 2d6 + constitution modifier cold damage. Star pact: The target also grants combat advantage until end of your next turn.
Effect: Hit both targets to teleport them and swap their positions.
Elder Constellation is an encounter power available to Warlocks at 7th level, and is designed for use with the star pact.
Elder Constellation was introduced in "Class Acts—Warlock: Strange Constellations" by Bruce R. Cordell in Dragon #403, an article meant to improve the ability for Star Pact warlocks to use Constitution-based abilities at certain levels.
It is an average choice, as it needs accuracy to function but it allows for an entertaining long-range position swap. [1]