Ancestral Vengeance (http://gatherer.wizards.com/Pages/Card/ ... eid=391790) gives the creature it enchants -1/-1, but when it comes into play it's supposed to add a +1/+1 counter to a creature of your choice. If you cast it on a creature that would still be alive after the -1/-1 you get to place a counter, if the creature would die it coming into play doesn't trigger. I think it's supposed to trigger, but the engine destroys the creature and it before checking for its comes into play triggers.

There might be more instances of this around.