A while back, DARPA took an interest in computer-controlling bugs; on the creepy-but-sensible premise that Team Neurology would probably manage to bodge on electrodes in the right places faster and cheaper than Team Robotics would replicate the small aircraft performance achieved by insects.
Mammalian subjects might be more of a squeamishness risk; but based on the number of seriously sneaky tricks employed by these squirrels, and their ability to carry a payload, it wouldn’t surprise me if the same logic would apply.
Certainly couldn’t work worse than bat bombs, right?
(And, in all seriousness, a weaponized squirrel could be pretty damn scary if the technical limitations could be overcome. They’d be naturals as wooded-area surveillance mechanisms; and given that they are nearly silent, visually unobtrusive, and capable of carrying surprisingly large payloads and executing long, controlled, glides, they could also be quite dangerous. As the unpleasant history of land mines demonstrated, a few tens of grams of explosives are enough to really ruin your day if delivered precisely; and a squirrel could do that, silently, potentially after skulking around in the foliage for hours or days.)
