The Marauding Bull of Crete
The seventh of Herakles' labors involved the mad and marauding bull of Crete, 
whom he had to
capture alive and bring back to King Eurystheus of Mykenai - his envious cousin
who ordered the twelve seemingly impossible tasks, and cowardly awaited in a pot
Herakles' return from each - or better yet, the news of his demise (which never came, of course).
The mad bull itself, laying waste to Crete, was a punishment by Poseidon to Cretan King Minos for
an earlier treachery.
Yet, this is not the last we will hear of this bull, as he was apparently
set free in the Greek mainland by Herakles,
where, having started devastating the Marathon area, he was eventually to be placated for good by another
classical hero - Theseus of Athens. Renditions of this labor, with Herakles usually subduing the bull by grabbing its horns, are predicatably rather scarce and prized.