A Spanish word that hopefully you don’t use much but unfortunately sometimes you need to is ácaro, meaning, “mite.”
Ácaro comes from the Latin for the same, acarus which ultimately comes from the Proto-Indo-European root *(s)ker‑, which meant “cut.” Perhaps the word for “cut” turned into “mite” because that’s what mites do, they cut you open?
From that same root, via German, English gets a bunch of word of words related to cutting, such as… scar. That’s just a big cut, right? We also get the English shore — that’s just where the land cuts the flow of the ocean.
We can see the c‑r mapping in both languages, with the initial s- disappearing in Spanish.