Illusionary Servant

• WWizards of the Coast2009-10-01
  Official Ruling
  If Illusionary Servant becomes the target of a spell or ability, Illusionary Servant’s ability triggers and is put on the stack on top of that spell or ability. Illusionary Servant’s ability will resolve (causing it to be sacrificed) first. Unless the spell or ability has another target, it will then be countered when it tries to resolve for having no legal targets.

Rulings via Scryfall