Shiva-class nuclear missile

The Shiva-class nuclear missile is a UNSC weapon.

Background
It is a ship-mounted thermonuclear missile, outfitted with a varying payload, a missile thermonuclear warhead assumable, to be anywhere from a twenty to eighty Megaton yield depending on its type (most of the missiles utilize UNSC standard 30-megaton HAVOK thermonuclear warhead).

Used by UNSC Capital ships and Cruisers, it can also be fitted on C709 Longsword interceptors for a low-profile insertion. They can also be fitted with guidance computers for increased accuracy. Upon detonation, the Shiva-class Nuclear Warhead releases a massive EMP (Electromagnetic Pulse), effectively disabling electronics aboard nearby ships.

It should be noted that Covenant Capital ship shields have enough power to absorb a full thermonuclear blast from far away, but not directly. If the warhead detonates inside the shield, the effects of the blast is multiplied tremendously, possibly due to the ship's shields containing the blast. This is demonstrated in the battle of Reach by Captain Keyes while piloting the Pillar of Autumn

Trivia

 * Shiva is the name of the Hindu god of both disaster and peace.