You attempt to interrupt a creature in the process of casting a spell.

1. The target spell must have a casting time of or greater.
2. spells, and Reaction spells, cannot be counterspelled, they are too fast to counter.
3. Spells cast from magic items CANNOT be counterspelled (they use Magic).

Both casters make a contesting roll. They both roll 1d20 + Bending Skill. Then the additional modifier is added to the counterspeller's roll: [spell_level_cast] - 3 (level of counterspell). Meaning, higher level spells are more difficult to counterspell.

A final modifier is added to the counterspeller's roll: if the counterspeller knows the spell, or is able to cast the spell, the counterspeller adds +2 to their roll.

This check is determined by the GM (or Janus automatically):

1. Failure
2. The target caster's spell SUCCEEDS and takes effect.
3. Success
4. The target caster's spell FAILS and has NO effect.
5. Tie
6. The target caster's spell FAILS, has NO effect, and both you and the target caster must roll on the Wild Magic Surge Table.