...how about a salt gun. Takes the fun out of tinkering toward your present project, but it will sting like hell.
The salt guns that shoot small powdered pepper spray/ tear gas balls are expensive but sure would put a sting on their. Lizard arses and eyes.
Maybe mix up your own mild version for a squirt gun?? Lizard napalm, without the fiery explosion.
Damn Invasive dinosaurs....just hang up a flyer about the coming meteor apocalypse. Alittle psyop action. If they remember the first one, maybe theyll blow town.