Tak is an explosive used in the book Pendragon: The Merchant of Death. Tak is an unstable explosive that takes the shape of a clay-like material and is found in Denduron, a place in the book that the main character is traveling to. Evil chacters in the book want to use Tak for mass destruction but Bobby, the main character, uses this against them for good.
On Denduron the Milago were actually born to wage war against Bedoowan. They plan to do this using Tak. They plan to kill the queen and most of the knights by exploding a large cart filled with Tak but they are stopped in time.