Here is another installment of exTRAPaganza, our Thursday over-the-top trap series.
Magic in here is unpredictable. Whenever a ray spell is used, there is a 25% chance that it fires off normally, a 25% chance that it instead strikes the caster, a 25% chance that it strikes a random target, and a 25% chance that it forks and strikes the target, the caster and 1d4 random targets. (targets may only be struck once)
This changes to 40/20/20/20 if a higher level spell slot is used, or 80/5/5/5 is a spell slot 2 levels higher is used.