Originally Posted by notabook

The easiest thing to do is to give it some meat (just about any will do, ham, spam, etc.) that has been mixed with about a 1/4 ounce of antifreeze. Granted, most feline exterminators will tell you that you need to use about half a ounce to get the job done but I assure you that this just isn't the case. A fourth of an ounce is plenty AND you have the added benefit that their organs will shut down more slowly than if you had used a half an ounce or more. By using less antifreeze, you actually cause MORE pain to the cat! Quite intriguing, really.

Honestly though in your case even that may be overcomplicating it. Just wait until they are going at it then smash them both with a huge rock. They?ll be distracted and you?ll be able to literally kill two cats with one stone.