I sympathize; I have to drive a good half-hour to find the one store that might carry blind bags, and both times I've tried they haven't had any.
Serum? Oh, it's nothing so primitive as that. You see, I've encapsulated the retrovirus in heat-resistant spores which I can slip into either sugar or flour, thus allowing me to deliver it via baked good.
On totally unrelated note, I'd like you to have these cupcakes I baked for you. *portals basket of baked goods to Dive Bomb*