Decided to check out the Ranch Ruins with my horse... And ran straight into two Guardians and a random Blue Bokoblin horseman. Broke two shields trying to deflect the lasers. Probably because I had decent armor(8+8, and +4 from a Diamond Circlet that gives resistance to Guardian attacks), as well as both shields having pretty good rating, instead of insta-gibbing me on impact, the lasers instead got deflected elsewhere as the shield was destroyed. One of them bounced off and vaporized the Bokoblin horseman.
Then, as the second Guardian was still exploding, I get run down by a Silver Bokoblin archer on horseback. I manage to shoot its horse from under it, but have to be revived twice via fairy in the process. A difficult fight ensues, but once the Bokoblin was on the ground, it didn't really have a chance.
After looking around in case the game decided to drop another boss-level threat on me, I come to a horrible realization: my shields were broken deflecting
two Guardian lasers. One hit the Blue Bokoblin on a horse. The other? ...My horse wasn't on the minimap anymore. And I had just learned that you can feed horses apples directly from your hand too.
Breath of the Wild. According to Malanya when I went to revive the horse, they died "bravely fighting a Guardian. A good death."