There are two items called "Spider Crab"

[Rongway]

Here's a rather crappily formatted list of the names in the different languages

Here you go:

Lang.     Item #20154       Item #29741
DE        Riesenkrabbe      Spinnenkrabbe
FR        Crabe araignée    Crabe-araignée géant
JP        タカアシガニ        スパイダークラブ
EN        Spider Crab       Spider Crab

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