Turns out the ads are based on The Book of Bunny Suicides, a comic book of cute little bunny rabbits attempting to off themselves in complex and interesting ways. Not the lightest of humour, but definitely fun. If you haven't see the book, you can just do a Google Images search for "bunny suicides" to see a whole bunch of pics from the book.
The dark humour tied in with that is usually such a light-hearted holiday (all pastels and Spring dresses and such) just makes me smile...
And with that, here is my fave loop of Creme Egg Suicides:
(Source: my frightened brain)