This weighted, opaque egg by SmartyKat can be quite a challenge for some kitties. Opaque toys are more difficult because the cat must go on learned previous experiences no longer having the visual cue that there is food inside. The weighted base of course provides more difficulty and to increase the challenge even further this toy can easily be placed inside larger foraging objects like the yogurt cup shown here. Now the cat must get the food out of two puzzles at once!