This jelly's bell can be white to dark purple/red, with dark lines radiating from the top of the bell. The species derives its name from the Greek words melas and aster, which translates to "black star" in reference to the pattern on its bell. Although not very venomous, their sting can cause an allergic reaction in some people. Their nematocysts (i.e., stinging cells) are powerful, capable of causing serious skin irritation and burning sensations.