(6/1/2020) If you reveal a companion outside the game, for as long as it remains there, you may pay any time you could cast a sorcery (that is, you have priority during your main phase and the stack is empty)
It's amusing to think about now, because of how tame Call of the Herd looks these days, but this was back in an era when creatures and threats were awful
WotC remains committed to ban problematic cards if they break the format like Vivi Ornitier and Cori-Steel Cutter, though they don't always remove the worst offenders right away
Of course, you won't win the game for drawing yourself either
Lightly played is slightly worse than near mint and is distinguished by more small imperfections
To make things even more ludicrous, you still get access to a second Commander through the Doctors Companion mechanic