Stuffing his ears for the purpose of stealing a bell
In the Spring and Autumn period, a thief had stolen a bell and intended to carry it away on his back, but the bell was too bulky and heavy to be carried, so he tried to break it into pieces with a hammer to make it easier for carrying. On his first hit, however, the bell made a loud noise. He thus feared that the ringing sound might be heard by someone, who would come to rob him of his bell. His fright made him plug his own ears, while hitting the bell with the hammer. The bell sound was, nevertheless, audible to others and therefore to stuff his ears for the purpose of stealing a bell was a stupid action it is as foolish as burying one's head in the sand.
from Huai Nanzi