The Screaming Bell is a large target and has a Unit Strength of 4 (5 with the Grey Seer).

The Screaming Bell has a Ward save of 3+ representing hits that bounce off the indestructible Bell of the Horned One itself. The Grey Seer does not benefit from this save, but gets the normal 5+ armour save from being on a chariot, representing the shelter he gets from the Bell's carriage.

Unsaved wounds caused by a hit with a Strength of 7 or more destroy the Screaming Bell automatically. On the other hand, every time one such wound is saved by the Bell's Ward save, the Screaming Bell will immediately ring with three dice as described below. Any new effects generated in this way replace effects that were lasting from a previous ringing of the Bell.

The Screaming Bell and the unit pushing it have Magic Resistance (2).

The Screaming Bell adds two dice to the Skaven pool of Power dice in the Skaven Magic phase. These dice can be used only by the Grey Seer.

The Grey Seer can take advantage of his high position, drawing line of sight for his spells over the heads of the Bell's unit (remember, the Bell is a large target). In addition, he is free to cast spells all around, not only in the unit's line of sight.