The Big One is probably the most cost effective grenade in the game (more powerful grenades, such as Thorium Grenade are extremely costly). It has enormous stun period, huge radius and good damage.
The Big One is crafted by Engineers with a skill level of 235 who also have the Goblin Engineering specialty.
|6x Solid Dynamite||1x Mithril Casing|
|1x Goblin Rocket Fuel||1x Unstable Trigger|
As an ingredient
The crafter will make two bombs at a time.