The Muck Master is a type of entity that manifests in Level 3: River of Ooze and Level 9: Lair of the Huge Spider with a yellow energy aura. It is weak against the Fermion Shock. However, keep a safe distance upon dispersing the entity. It will unleash a shockwave in its wake.
- On page 3, panel 2, of Ghostbusters Annual 2015, right of Egon Spengler, on the cement bag is labeled "Muck Master Cement" - a non-canon reference to the Muck Master.