A friend from way back had one as a pet. It spent 95 percent of its time curled up into a perfect spiny ball, breathing asthmatically & emerging only to eat & shit. If you (carefully) picked it up, touched it or blew air at it –if it detected your presence in any way– it would only squinch up tighter & breathe faster. I remember finding this so infuriating that I had to suppress the urge to put it in a bathtub and start filling it with water just to see if it would un-ball itself to keep from drowning (for all I know it would’ve floated.) The most non-interactive pet ever…”Sonic” my ass.