This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
螐 combines 虫 (insect) with 烏 (crow/black), but the exact historical development and original meaning are uncertain.
The insect radical 虫 beside the crow shape 烏 suggests a dark insect, but the meaning is unclear.
For オ, imagine an old crow (烏) with an insect (虫) on its back, and the crow says 'Oh!' (オ) in surprise.
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