Assertion: magician's spell | /r/AtLocation | the stack
Facets:
Source sentences:
text: These spells must be cast while the spells they will affect are still on the stack.
text: A spell can't be cast without a legal target; if the target becomes illegal while the spell is on the stack, then the spell is countered by the game rules (for having an illegal target) just before it would start to resolve.