Myr - Heart of Saltpeter

From my personal project of Myr:

The Hearts of Saltpeter is one of the organic créations of Myr dedicated to warfare. Sent to borrow into the ground ahead of enemy forces, and once walked upon, violently explode.

For more details on them, or the lore of Myr at large ->
https://sites.google.com/view/myr-worldbuilding/myr/alchimie-organique/codex-des-alchimistes