2000 dixie cups filled with red kool-aid on their lawn delivered in the same manner as your newly acquired forks.
Of course you'll need a few accomplices to get the job done quickly.
One with the cups, one with a super-soaker filled with the kool-aid and one to place them. Better yet would be a few teams like this.
Maybe even put one of your forks in each cup as a calling card.
