I think everything either has DNA if it's living or a captcha code if it isn't. Part of the comic is how anything can be invoked by simply knowing the right series of symbols to represent it.

True enough, but I would have to add that, the fact you can Captchalogue a Human Corpse and a Living Consort imply even living things have Captcha Codes. Also we even get Dave’s Brain in a Jar as a Captcha Combo, so, yeah.