Tola'at shani — the crimson worm

The same word, in a completely different register. תּוֹלַעַת שָׁנִי, "worm of scarlet," is the Tabernacle's crimson — the dye named for the insect it is crushed out of, listed beside blue and purple and fine linen in the instructions for the curtains, the veil and the priest's garments (Exodus 25–28), and used again in the purification rites of Leviticus 14 and Numbers 19.

So the word worm sits in scripture in two places at once: as the small helpless thing in Isaiah's comfort, and as the source of the most costly colour in the sanctuary. The same creature is the emblem of weakness and the supplier of the holy red. This is not a pun the tradition invented — it is a fact about dye chemistry that the language happened to preserve.