Return to Oblivion (11 Essence)

Effect: You create a size 1L vortex that lasts until the end of the encounter. At the start of each combat round while the vortex is unoccupied, the vortex vertical pulls 3 each enemy within 5 squares of it. Each enemy who enters the vortex or starts their turn there is knocked prone. At the end of the round, if a winded enemy who is not a leader or solo creature is in the vortex, they are instantly destroyed.