I actually didn't see this in my inventory. Same with Category Pets And Costums.

Same here. I mentioned this on the lua event chat a few days ago, and others had the same problem, but it looks like nobody has gotten around to fixing it yet.

Out of curiosity, I used 400 of those stupid shells to buy 80 green bugs. I wanted to see if they actually count on my profile. I couldn't buy more after 80 (I still had 100 shells left over), so it seems that the game keeps track of how many green bugs I have, they just don't show up. Which, of course, also means that they can't be used...