Mouser's Scalpel

)   Mouser's Scalpel   (No tile)
Base item	rapier
Damage vs. small	1d6 +1 + (special)
Damage vs. large	1d8 +1 + (special)
To-hit bonus	+5
Bonus versus	(any)
Weapon skill	saber
Size	one-handed
Affiliation	neutral
When carried	(none)
When wielded	(none)
When invoked	(none)
Base price	600 zm
Weight	40
Material	metal

Mouser's Scalpel is an artifact weapon that appears in SlashTHEM and Hack'EM. It is neutral for wishing purposes, and its base item is a rapier.

Description

The Mouser's Scalpel grants +5 to-hit and +1 damage, and has a unique mechanic that allows it to deliver extra "attacks" on each hit: these extra attacks deal +1d8 + 1 + <enchantment> to all monsters. Each hit has an initial ¹⁄₅ chance of delivering one of these extra blows, followed by a ⁵⁄₁₁ chance of subsequent additional hits, applied repeatedly until this chance is missed.

Strategy

The chance for extra blows to stack means that in theory, the wielder may be lucky enough to continually strike a foe indefinitely until they are killed.

Average damage calculation

The average damage calculations in the following table do not include bonuses from weapon skills, strength, or from using a blessed weapon against undead or demons.

Given unique nature of the added hits, we first need to find the expected number of hits per swing of the weapon. Given that the initial bonus strike has a ⁴⁄₅ chance of no hits, a ¹⁄₅ chance of occurring the first hit, and the probability p on subsequent hits after that, we can write the equation as:

Expected number of hits
$0*80%+(1+\frac{1}{1-p})*20%=(1+\frac{11}{6})*20%=\bold{0.57}$

With this we can then calculate the expected amount of damage from the proc as:

Expected damage from extra hits
$(\frac{1+8}{2}+1+enchant)*57%=\bold{3.12+enchant*57%}$

Weapon	Small monsters	Large monsters
+0 Mouser's Scalpel	$\frac{1+6}{2}+1+3.12=\bold{7.62}$	$\frac{1+8}{2}+1+3.12=\bold{8.62}$
+7 Mouser's Scalpel	$\frac{1+6}{2}+1+3.12+ 7*57% +7=\bold{18.61}$	$\frac{1+8}{2}+1+3.12+ 7*57% +7=\bold{19.61}$
+9 Mouser's Scalpel	$\frac{1+6}{2}+1+3.12+ 9*57% +9=\bold{21.75}$	$\frac{1+8}{2}+1+3.12+ 9*57% +9=\bold{22.75}$

History

The Mouser's Scalpel first appeared in SLASH 6 as one of the many "Newhon" artifacts; it was then known simply as Scalpel (not to be confused with a Healer's scalpel), and became a deferred item within the data of SLASH'EM, which carried over its code. The artifact was renamed and reintroduced in SlashTHEM, which adapted it from BarclayII's SlashEM-Up project.

Origin

The Mouser's Scalpel comes from the Fafhrd and the Gray Mouser stories by Fritz Leiber, where it is the titular Gray Mouser's trademark weapon. His prowess in swordsmanship is reflected in its ability to strike multiple blows.