Cats are well known for getting into lots of different things they are not suppose to... including your Easter Egg Stash. This can be a dangerous combination as chocolate contains certain properties that can be toxic to cats. When Chocolate is ingested, these ingredients lead to various medical complications and may even prove fatal for your cat.
So Make sure you keep a count on all your Easter Eggs to make sure the kitties aren't trying to steal any.
The amount and type of Chocolate ingested by your cat is important, as they are determining factors for the severity of the toxicity. If you suspect your cat has ingested chocolate, you should immediately take your cat to be examined by your Vet.