My 90's childhood trauma resurfaced here.
I pressed + a few times to keep making the horse bigger, which made me happy, and wondered "How far can I go with this?"
So I pressed it a few more times, with diminishing results, and then I started feeling anxious for some reason. I realized I was thinking "Wait, this is a setup. How long until it turns into a horrifying face and screams at me?"
Too many old gimmicky sites/flash games that cause users to focus more intently/rush on through before throwing in a jump scare. Always hated that stuff.
Based on the other comments though, I'm relieved it seems to be an innocuous site that just helps a horse achieve its dream of becoming as big as it can possibly be.
FWIW I initially just took this in the context of the source material, Game of Thrones.
Cersei Lannister (pictured) comes from a noble house whose sigil is a lion. They use a lot of lion metaphors. One of the quotes from her father Tywin (in the show at least) is "The lion does not concern himself with the opinions of the sheep."
Cersei as a character, though, is a bit of a hot mess who makes it her business to concern herself with everyone.