He fell off his horse because he was laughing .None of the above choices .He did n't pay attention and fell into the horse manure .He made his part of his friend blow up .
What stopped James 's laughing fit ?
James , in a fit of laughter slapped Artie 's back , and for some reason , this caused Artie 's head to randomly explode . James stopped laughing and turned to look when his horse suddenly reached up , with its neck stretching to accommodate its actions , and bit off James ' head . Both human bodies then fell off their horses , only to sink like bricks in quicksand in a pile of horse manure .