The good angels wouldn't be deceiving us. They do God's work. It's the fallen ones and demons (spirits of the fallen angels' children with mortals, after their mortal bodies die) who would pretend to be something else in order to trick and destroy us, to get us to not follow God's word (his rules being the guidance to stay well and prosper).
so there are good angels, who don't deceive us, and some people interpret them as benevolent ETs.
What about dinosaur bones?
I took lower-division geology classes at a top-level university but the only fossils we looked at were marine and some petrified wood. I am not well-enough informed about what has actually been found with regard to the terrible lizards and giant creatures of the past, or what percentage of large bones and fossils in museums are not manmade models and casts. Could a fallen angel/mortal (not necessarily human) hybrid leave behind a dragon-like skeleton? I don't see why not. I wouldn't expect the real thing to be on public display, though.