any advanced technological device, usually pointless and/or confusing. similaly: gadget, widget, whatchumacallit, etc.
palm pilots, global positioning systems, radar detectors, digital camera widgets, generally anything small and electronic.
Much like the gremlin Gizmo, only in human form. A spoiled child. The child is cute and cuddly until you piss them off by telling them the dreaded word "No" then they turn into a hideous little monster.