IPA: /ˈwɜːrmˌkæst/
KK: /wɜrmkæst/
A small mound of soil or sand created by earthworms as they break down organic material.
The garden was full of wormcasts, enriching the soil with nutrients.
Wormcast → The word is formed from "worm" (from Old English "wyrm", meaning serpent or worm) and "cast" (from Old English "castan", meaning to throw). The term refers to the castings or excretions thrown up by worms, particularly earthworms, enriching the soil.
Think of a 'worm' ('wyrm') that 'throws up' ('castan') its castings, which are beneficial for the soil.
No commonly confused words.