bubble
n.— «“Have you ever tried “crystal’?” he asked, bringing out crystal methamphetamine and a small glass pipe that some refer to as a “bubble.”» —“States Grapple With Growing Teen Meth Use” by Martha Irvine in Lake Elmo, Minn. Newsday (Long Island, N.Y.) Apr.10, 2005. (source: Double-Tongued Dictionary)