The Megashark is a ranged weapon that was added in the 1.1 patch. It is crafted out of the Minishark, Illegal Gun Parts, 20 Souls of Might and 5 Shark Fins. It deals 25 base damage per hit, and has a 50% chance to not consume ammo (essentially making ammo last twice as long, give or take some depending on the player's luck). Due to its stats, it is easily one of the best ranged weapons in Terraria, especially with its best prefix (Unreal) and ammo tailored to specific combat situations, like Crystal Bullets and Cursed Bullets. The Megashark is well known as an extremely powerful weapon, due to its incredibly high DPS. It can use any bullets, however expensive bullet usage is recommended for non-general situations as the Megashark consumes ammo at an incredible rate.
The weapon has extremely weak knockback, but the high rate of fire will keep most enemies at bay from the sheer number of hits.
Oddly, the Megashark is worth less than the Minishark when being sold to a vendor.
Combined with the Necro Armor, this weapon has a 60% chance of not consuming ammo.
On the console version of Terraria, when the Megashark is used in conjunction with the full set of Titan Armor, you have a 64% chance to not consume ammunition.
Unreal is the best prefix this item can have. See Reforging for the full list.