noun
errand
AIR-und/ˈerənd/
A short trip made to carry out a practical task.
She runs an errand to mail a letter near her home.

Etymology
Old English ærende referred to a message or mission, originally an important one. The meaning later narrowed to a short, simple journey made to carry out a task.
In context
certain you left the body here?" "Certain?" I echoed. "Why, look at the hole I made. You don't think I have any interest in leading you here on a fool's errand, do you?"