Weird Spam-with-no-links clogging my GMail

This week, I seem to have fallen victim to the most bizarre kind of spam.. ..spam that isn't. In other words, nonsensical emails that don't actually contain any attachments or links to websites.

Examples:


I'm getting dozens of these every day; the sender and body seem to be chosen at random from an English dictionary each time. The worst thing about them is that they pass right through GMail's spam filters without being stopped. Presumably because the email doesn't contain any links or attachments - so it's technically not spam.

I'm at a loss to explain what's caused this; perhaps a rogue spambot somewhere that's forgotten to actually include the crucial link or attachment? Or some sort of guerilla spamming exercise?

Frustratingly, there is no easy way to filter them out.