This egg was only available in Egg Cave's Cash Shop Park for March 2015.
Early into their development, Dianesia eggs are very soft and jellylike. However, they also have microscopic thorns on their surface. Handling these eggs without gloves or other protective instruments will cause some of these needles to become embedded into your skin, and because they aren't visible, they're very difficult to remove!
When a Dianesia egg is close to hatching, the egg hardens. The needles retract back into the egg, and embed themselves into the shell. This helps the developing creature to crack the egg when in the process of hatching.
Dianesia are relatively standard in terms of size and behavior in comparison to that of other butterflies. The most unique thing about them is that they only come out during the rain. Despite their small size, they actually enjoy being hit with falling raindrops. They require large amounts of water to stay hydrated, although the reasons as to why they require so much water without appearing to expend large amounts is unknown.