I recall reading that lord Siva killed Varaha, Visnu's boar incarnation. Is it true? Is this in any scripture? Apparently, Narad, the sage, took offense seeing the mother suckling her cubs. Somehow Siva got word of this and soon after he killed the mother (I assume with his trident). This is followed by Visnu reappearing - like the genie from Aladdin I guess - laughing off the whole thing, knowing his boar incarnation is just maya. Is there a source for this story?
note: there is another question here about lord Indra killing a boar, but I'm not sure if it's the same incidence.