This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
蛠 combines 虫 (insect) with 劦, but the exact historical development and original meaning are uncertain.
With 虫 (insect) on the left and 劦 (a shape associated with cooperation or strength) on the right, you might imagine a cooperative insect, but its meaning is unclear.
For レイ, picture a ray of light shining on a mysterious insect: ray -> レイ, and the insect is 蛠.
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