Uh... the Japanese uses the word "effect part" (in katakana English) for, well, things you stick on or glue on to imitate "special effects" like beams firing or electric arcs or the air from wings beating or... in this case the "spinning effect" (motion blur, air spirals, etc.) of the palm drill of the Z'Gocky. Does the English-speaking Gunpla commmunity have their own term for this?

Speaking of which this arc is filled with so much jargon (some abbreviated like "Web") I was basically like @_@ and had to delay the TL for later until I was able to look up the terms and get things sorted out.