The bearer of the Skull of Katam can choose to consult it before attempting to channel power dice. If he does so, roll 6 dice instead of 1. If the bearer consulted the Skull of Katam, he suffers a -1 Leadership penalty for the rest of the game for every result of a 1 roll when channelling - if it is ever reduced to 0, he is immediately removed as a casualty. A Wizard with the Mark of Tzeentch may not re-roll channelling results of a 1 when using the Skull of Katam.