|Ah! General Hornworm, I presume!|
I've done some research on these guys, and I think what I have are not tomato hornworms but tobacco hornworms (on account of their red horn). People on the internet have told me to put them in a cup of water, slice them in half with gardening shears, feed them to birds, encourage wasps to parasitize them, and spray them with Bacillus Thuringiensis which kills them by causing gut paralysis and subsequent starvation combined with tissue damage.
I have opted to hold a plastic flower pot under each hornworm and snip off the leaf it's sitting on. Then I take it out to the front yard and throw it into the garbage bin there. I'm not yet sure how successful my method will be because these hornworms might have vastly larger reservoirs of willpower than I give them credit for. For all I know, armies of hornworms are presently advancing upon my tomato plants, having survived the heat and somehow scaled the smooth walls of the trashcan. They might have tiny drums and tiny bugles and tiny tattered flags and a tiny hornworm general (General Hornworm) and tiny night vision goggles, for all I know.
We might wind up in an all-out war before the week is through.
* Not a euphemism.