The Idea of this creature is that it Travels the deserts and slowly follows animals(and humans) who look like they are faint of life. The creature attacks only when the prey is weakened to the point where it cannot defend itself.
Each victim it consumes is turned into an acidic sap that it stores into column-like sacs on it's back, which will the Morvanger will explode if every attacked. Desert Tribes sometimes worship the Morvanger's as they believe they are walking graveyards that ferry the dead between worlds. Some of these fanatics will send their elderly out to search for Morvanger's to shepard them to their afterlife.
I hope you like, was fun!