Picador (Spanish). A horseman; one who in bull fights is armed with a gilt spear (pica-dorada), with which he pricks the bull to madden him for the combat.

This is a very nice, fancy etymology, but it's a bit baroque. The spanish word picar means "to prick" or "to puncture" (or lots of related poking verbs - it's also related to the word pike, the long spear used by infantry against cavalry), so someone who tortures the bull this way would be a picador - an ugly translation of which might be "pricker." So I have my doubts about the golden pike suggested in this etymology.