One time, I did not heed the advice to not over-pump one of these. I was kneeling in the grass, pumping it up. I remember seeing it, then in the next moment, the rocket disappeared in an instant and everything went quiet. I realized it exploded, probably with a very loud noise, and it took me a few hours for sound to come back and the ringing to subside. Luckily I didn't lose an eye (though I did wear glasses, which probably helped).