The SanDaikaijuMosuLarva's name comes from Ghidorah, the Three-Headed Monster's Japanese title, specifically san daikaiju (三大怪獣?), meaning three giant monsters, Mosu, from Mothra's Japanese name, Mosura (モスラ?), and larva, from the fact that it is a design for Mothra's larva form.
The SanDaikaijuMosuLarva is mostly based on the previous Mothra larva design, as its body proportions and the shape of its face are mostly unchanged. The SanDaikaijuMosuLarva's body is now smooth, without any visible wrinkles or veins, and is a dark brown color all over, with no spots. The eyes are red for the first time instead of blue, and the feelers next to the mouth have returned to a slimmer and more even shape.