Wild Surge
When a Channeling check goes wrong (or very right). Pick the spell's school and enter its Total Strain (base + delivery + modifiers); the severity follows. Rules: Magic.
READY
Choose the school, Strain and result, then roll.
You may ignore a surge result if you choose. If the effect refers to "the target" and the spell had several, pick one at random; with no targets, it hits the caster.