The Disco Zebra Midgeling is a pattern derived from combining the Disco Midge pattern with Mike Mercer's successful Zebra Midgeling pattern. Mercer's pattern is based off of the ubiquitous Zebra Midge, which is about as simple as a pattern can get: a thread base, wire ribbing, and a metal bead head. Mercer modified the Zebra Midge by adding triggering characteristics to the fly to help entice reluctant trout to feed. 
The Disco Zebra Midgeling has proven to be an effective pattern dropped under a dry fly like a small caddis or Griffith's Gnat, as well as drifted deep as a dropper off a bigger nymph.