i've driven a lot in highways... i've seen a lot of things i've mistaken as dead animals, so i hope it consoles you to know i've been there too...

and i too feel anxious about it... maybe sometimes a bit depressed to think a small animal as helpless as a cat, dog, or something else would lie there in its dying... so maybe that's similar to what you described...

i remember accidentally finding a graphic video of a cat with a broken spine alone in the middle of the woods, and that really got to me for a long while... i notice it's the same emotion i feel for roadkill so... maybe that... dunno...

overall, empathy is what it is... i guess...

if the first... you mean peripheral vision, i guess it's just everyday hallucinations... i remember looking up my own small hallucinations similar to this, found out it's very common. but maybe you associate it with lizard droppings for some reasons unique to you... idk... just like hallucinating people you knew on people that look like them. i think it's really odd you specifically say "lizard" poop though... haha...