Adam Clarke on 1 Kings 12:11

Chastise you with scorpions - Should you rebel, or become disaffected, my father's whip shall be a scorpion in my hand. His was chastisement, mine shall be punishment. St. Isidore, and after him Calmet and others, assert that the scorpion was a sort of severe whip, the lashes of which were armed with iron points, that sunk into and tore the flesh. We know that the scorpion was a military engine among the Romans for shooting arrows, which, being poisoned, were likened to the scorpion's sting, and the wound it inflicted.