I've read about them. They're an explosive that detonates a set time after you activate them and throw them. We have weapons like that, although they're chemical-based.

[Answer: he knows about them in theory.]

Are you...suggesting that I make one? I can't say it will work like the ones of this world, but I could tinker up one based in alchemical principles and some magic. Something infused with an explosions spell? A fireball?