From Thinkgeek:
The company that manufactures these shared their origin story:
We were stocking our warehouse when one of our original Featherstone pink flamingos was bit by a sickly warehouse pigeon.
These red-eyed, black-feathered flamingos with fangs which resulted are ready to haunt your yard. This set of two in different poses comes with four metal rods for legs. They’re as easy to put in the ground as a “For Sale” sign. Which is what your neighbors might do once they see your flock.
