Ketamine users get "robot feet" when they've squirted so much up their ass that they can no longer tell which way is up. They agonize over every step they take and very slowly perambulate, almost as if their legs were robots under remote control. To sober witnesses this behavior is hilarious. See ketapillar.
I got such bad robot feet it took me forty five minutes to walk all the way upstairs. By that time I was almost sober.