I’m going to sound like such a snob but nothing really “spooks” my horse. There’s no running away or bolting or bucking, once and a while he’ll spread his legs like a newborn deer if he’s feeling a little frisky and something startles him, but other than that he’s pretty bomb proof.
He’s in his mid-20s (still going strong though! Acts like he’s no older than 10) and has basically seen and done everything as my instructor has a theory he was an eventer some point after his racing career (tattoos to prove that, but only his training speaks for the rest of it).
Plastic bags, nope. Cars backfiring, nope. Loud, obnoxious farm equipment, no reaction. Riders falling off and horses loose, nothing. Flapping pieces of cloth, doesn’t even bat an eyelash.
But what he does do? Stare. Like rigid, no movement, no breathing just staring straight at whatever he’s transfixed by. It doesn’t happen too often but the other day my instructor’s son was driving his mini toy tractor on the driveway that snakes next to the ring and all Jester wanted to do was stare at it. Even when it got really really close he didn’t freak out, he just wanted to stare at it like it was the most interesting thing on the planet lol.