Looks more like and Aiptasid to me. As far as multiplying, depending on the species and the conditions, it could be anywhere from sending out swarms of offspring each week to never reproducing unless forced to by being damaged. For species that can send out small armies of new nems, the rate is usually depenedent on food and lighting conditions to some degree (a bigger army with more food in particular). You don't need to worry about getting your hand on it unless there's something else on the rock your'e worried about. Some Aips are fairly sticky when they contact human hands, but only one I've ever come accross gave me just a bit of a tingle. Don't bother trying to starve Aiptasids - any bit of light is enough to keep many of them going and failing that they can feed on moderately-sized particulates in the dark as well as any small bugs running around on the rock. So, unless your tank is pitch black and sterile, you'll have a hard time controling its food sources.