lobster moth
A moth species (Stauropus fagi persimilis) whose caterpillar resembles a lobster or a shachihoko ornament. The name is usually written in katakana.
The larva of the lobster moth looks just like a tiny shrimp.
Katakana spelling is standard for this moth name; usually written in kana.
Rare kanji spelling; the first character 天 is an ateji-like usage, and the full form is seldom seen.
Rare kanji spelling; 鯱 (shachi) refers to a mythical carp-like creature, used here for its shape resemblance.
The name シャチホコガ comes from the caterpillar's resemblance to a shachihoko (鯱), a mythical carp-like roof ornament. The exact derivation is uncertain, but the shape is the likely source.