Dead men may rise again, like Bayes's troops, or the savages in the Fantocini (Something New). In the Rehearsal, by George Villiers, Duke of Buckingham, a battle is fought between foot-soldiers and great hobby-horses. At last Drawcansir kills all on both sides. Smith then asks how they are to go off, to which Bayes replies, “As they came on- upon their legs”; upon which they all jump up alive again.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894