This mutation grants the ability to instantly alter the body density of a target, thus shrinking or enlarging, with maximum enlargement up to twice the natural body size. Each fraction of a body size change is accompanied by an equal fraction increase or decrease to armor class and speed. For example, reduction of size by 1/4 also reduces (improves) armor class and movement by 1/4. Becoming twice as large increases armor class by a multiple of two (to a maximum of 10) and divides movement in half as well. Note that reduction of body density to 1/8 makes a character impervious to damage from sharp implements.
This mutation has a range of 90 feet, a duration of 1d4 turns, and cannot be used on the mutant who wields it.