From view source:
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endless.horse
Colleen Josephson and Kyle Miller, 2015
Created during the West Coast Stupid Shit No One Needs & Terrible Ideas Hackathon
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It's wonderful seeing this pop up occasionally. As boing boing once said, it's not called endless for nothing.
We personally use https://secure.endless.horse/ as a quick check our internet connections, especially when there's a captive portal.
We tried adding endless.horse to a database of non-phishing urls (after all, it's merely an ASCII art horse with abnormally long legs), but the one we were pointed to by the security researchers hasn't allowed new accounts for the last two years. It's a strange being implicated in this indirect way -- Does endless.horse condone phishing? The horse says "neigh."