INDEPENDENCE, Mo. -- A retired high school teacher was crushed to death Tuesday when a small farm tractor flipped over while he was pulling out a fence post.

Carl MacDonald, 60, of Independence, had attached a chain from the tractor to a 9-inch-diameter fence post that stood about four feet high, police said. The chain yanked the tractor backward until it flipped, end over end.

His wife found him under the tractor in the back yard.

"He's my entire life," Shirley MacDonald said. "He used humor and made everything wonderful."

MacDonald's friends said he often dressed up for staff parties at William Chrisman High School.

After 25 years at the school, MacDonald retired in 2002 as a social studies teacher.