Boomelancer: Spinning Assault Blue Lancer (回転して突撃する蒼い槍兵, Kaitenshite Totsugekisuru Aoi Sōhei?) is a comedic Noble Phantasm used by Berserker in Carnival Phantasm. Berserker, sent on an errand to buy batteries for Ilya, meets his "good friend" Lancer, who is forced to join him on his task. When fighting against Archer for a package of batteries, Berserker utilizes Lancer as a melee weapon to engage him. Though Berserker normally only has one Noble Phantasm, Boomelancer is a unique Noble Phantasm created by using Lancer as a thrown weapon.
The weapon emits a blue light as it spins around rapidly while striking everything in its path without fail. While it has the effect of a penetrating javelin of death, it does not return to the hand of the thrower like a boomerang. It requires Berserker to seek out and find Lancer after its use. The ability has a critical effect on Archer.