Not all creatures fight with discipline, but flail about in an uncontrolled manner, with unpredictable consequences.
Source: Warhammer Fantasy: 8th Edition
Random AttacksURL Copied!
Models with the Random Attacks special rule do not have a normal number for their Attacks characteristic, but rather a dice roll, such as D3, D6 or D6+1. Each time a model with this special rule comes to strike blows, roll the indicated dice, adding any modifiers shown, to determine the number of attacks that the model will make, then roll to hit as normal. If a unit contains more than one model with Random Attacks, roll separately for each model, unless specified otherwise.