Paralysis forces victims to collapse or stand rigid. Instead of delivering instant Wound Points, the damage determines the severity of the paralysis.
Instead of normal wound points, you cause paralysis rating. For every 5 points of Paralysis Rating (rounding down) the victim suffers 1 point of Impairment until cured. When impairment equals the character's Constitution, he is entirely helpless, and can no longer fight the condition. Paralysis can be cured just like ordinary wound points.
At the cost of a Magic point, you can do both damage and inflict paralysis.
If you must always use this, and thus cannot use the blast power to do normal damage, the metablast schtick is free.
Similar to Curse.