muckworm

noun2

1. •
   A larva living in mud or manure.
2. •
   Someone who gathers wealth through overwork of employees and sordid means; a miser.

   • Here you a muckworm of the town might see, / At his dull desk, amid his legers stall'd, / Eat up with carking care and penurie; / Most like to carcase parch'd on gallows-tree. — 1748