[Games Workshop] is in the habit of creating differently marked dice for its games, rather than using [look up tables]. These new dice are invariably [D6]es, as Games Workshop really hates dice with an unusual number of sides (perhaps because square dice are easier to store, or perhaps because [polyhedral dice] make the hobby seem too nerdy).

Once they've invented a new funny dice, Games Workshop go to great lengths to incorporate it into as many games as possible, whether it simplifies the game or not. The [Cannon of Khorne] was introduced in a [Space Marine] supplement, so as to justify bundling an [Artillery Dice] (I can count on one hand the uses of an Artillery dice in Space Marine). The [Skullcrusha] cannon, introduced in [Titan Legions] is particularly contrived, being the only weapon in a game system consisting of two boxed games, and four supplements that uses a [Sustained Fire dice].

The numbers on Funny Dice are all [Arabic Numerals], not spots, so they are easily distinguished from regular [D6]. [Funny Dice] with some numbers the same are different colours, so they may be easily distinguished. Funny dice include:

Artillery Dice: white, 2cm, 2, 4, 6, 8, 10, "misfire"
Sustained Fire Dice: red, 2cm, 1, 1, 2, 2, 3, jam symbol
[Scatter Dice]: white, 2cm, protected by [patent]
[Epic] Aim Dice: white, 2cm, "", "", "", "", "up"/"left", "down"/"right"
Epic aim dice are used in pairs - one has "up" and "down" printed on it, the other "left" and "right".
[Space Crusade] Dice: white, 1.5cm, wooden, 0, 0, 1, 1, 2, 2
[Space Crusade] 'Heavy Weapons' Dice: red, 1.5cm, wooden, 0, 1, 1, 2, 2, 3

Games Workshop's Funny Dice (thing)