I think we've had a similar TOD before, because I think I've posted this before, but I will do so again. Ah, memories.
Not really "foolish" per se, but two horrible/funny things happened whilst I was playing Bill Sykes in OLIVER! The director had decided to have me use my own dog, a Basset Hound, for Bill's dog. And she had done very well in rehearsals. On opening night she must have "caught wind" of the audience, because as soon as I took her out in Act II (which opened with me singing MY NAME, IIRC), she just freaked out and refused to move, digging her claws into the stage. I handed her leash to one of the ensemble, sang my song, and then proceeded into the dialogue scene. I motioned to the ensemble member to take the dog off the stage. Instead this idiot girl walked her around the stage and then brought her back and handed her to me. Now the problem is, the set was gigantic, with two sets of stairs leading up and out into the wings. And that's how I had to make my exit. So here I am dragging my poor dog, who did not want to move, literally yanking her up an endless flight of stairs. It was in the early days of laveliers (am I dating myself?), and the sound tech unfortunately forgot to turn my mic off, so the entire chaste Mormon SLC audience was treated to me whispering fervently, "Come on, you f***ing dog!"
Moment two, from the same show. One performance the retractable knife did not retract when I stabbed Nancy. And due to one of those horrble things that seem to occur now and again, the actress had her head in a slightly different position than she usually did and I hit her lip. It split wide open and a gush of blood literally spurted up and over both of our heads. The audience thought it was a special effect and "ooh'd" and "aah'd" and actually applauded.