Scientists at Penn State would like to release tiny spiders into your blood -- no, it's not the premise for a new horror movie, but rather, it's a medical breakthrough. The spider-like machines are less than a micrometer wide (just so you know, a red blood cell is around six to ten micrometers), and are designed to travel through veins delivering drugs and a little TLC to damaged areas -- not a totally new concept , per se, but even minor advancements can open up all sorts of new doors for troubled patients. Made of half gold, half silica, these microspiders are self-propelled by a molecule called the Grubbs catalyst, which scientists can control directionally using chemicals. Although still in the preliminary phases, lead researcher Ayusman Sen hopes to one day attach the creepy crawlers to nanobots, which could maneuver through the body to detect tumors , helping the immune system and scrubbing vessels clean of plaque. Not like that's doing anything to diffuse your arachnophobia, but hey...