Producer and director Russell Blackwood is an expert on stage blood. He knows how to make it dribble or spray, or flow from actors' mouths. He also knows how to poke out an eyeball, complete with membrane. In fact, he experiments with stage blood so much that he often comes into our office, where we work together, with faded stains from his fingernails up to his elbows. Besides this suspicious-looking coloring, the other thing that distinguishes Blackwood is his wicked belly laugh. It's no wonder that he presides over the city's only theater company to gleefully honor horror and dismemberment, the Thrillpeddlers, now presenting the exuberant, if slightly uneven, at its SoMa home, The Hypnodrome.