The nuclear explosive (also known as a nuke), is a very expensive but powerful explosive. The explosion radius is huge and will kill any entity that is within its vicinity. It is not recommended to use this on friends and on worlds that are not backed up.
The explosion will not only destroy obsidian, but will create nuclear fallout which spreads throughout the land over time. Any living thing that goes close enough to the fallout zone will get Radiation Poisoning, and their hearts will turn black (like the wither effect) and decrease rapidly for approximately 40 seconds. The fallout will spread onto any grass blocks or blocks that are living (such as tall grass, bushes and shrubs). One can maintain a fallout from spreading by making sure all blocks that contain living things are far far from the fallout zone. In addition to that, one can clear out a radiation zone carefully by breaking all the radiation blocks and cleaning up the crater.
Notice that since the game has been updated, the crafting recipe for the Nuclear Explosive no longer works! Until the crafting recipe is released or discovered, the only way to get a Nuclear Explosive is to spawn it into the game through creative mode, or through the NEI "Cheat" menu.
Antimatter explosives are crafted from 8 antimatter capsules combined with a nuclear explosive.
Missile form of the above Explosive