schematics for a lizard gun, aka schematics for a lizard gun, schematics, lizard, and gun

Plans written on a napkin for the creation of a small hold-out dinosaur.

It tells you how to make a lizard gun with the following components:
1 - dinosaur toy
1 - short steel pipe
1 - rusty metal spike
Making this would take decent familiarity with craft and decent familiarity with pistols.
In the upper right corner is a note: 'First discovered by Dr. Ilids.'

It weighs about 100 grams. It is a gun schematic. You think it might fetch about $2 on the market.