Type 14 Magnetic/Anti-Tank Mine

The Type 14 Magnetic/Anti-Tank Mine is a UNSC explosive. This is also used as "the bomb" in Assault-type games from Halo 2 and Halo 3.

Background
It's used as both a mine and a satchel-charge type bomb. The arming fuse can be set for five, ten, or fifteen seconds, and has massive area of effect damage. The magnetic attachment device ensures that it will attach to a vehicle which passes over it.

Trivia

 * It's used to portray Andy in the machinima series Red vs. Blue.
 * There are messages written on the bomb.
 * It has been remade for use in several custom maps on Halo Custom Edition, including Extinction.
 * It is the object used in the game type: Grifball.

Messages
The messages seem to correspond to what map is used.

For instance, the message 'Thus I Refute Thee' appears on the maps Ivory Tower, Waterworks, Turf, Backwash, Elongation, Relic, Foundry. On Bungie.net's matchmaking stats section of the service record, the description of the bomb is "Thus I refute thee."

'Hold Onto Yer Butt' appears on Ascension, Burial Mounds, Warlock, Gemini.

'Kiss It Goodbye' on Coagulation, Headlong, Sanctuary, Terminal and on Tombstone as well.

Hieroglyph of a Spartan helmet, the two fingered peace symbol then xoxo and hearts; appears on Lockout, Midship, Beaver Creek, Colossus, Zanzibar, Foundation, Containment and on Desolation.