Black silk with that much damage? More probably nylon
What about
Spiny whip "the Manticord" (+0, 7d3 + 3) (15s) (one-handed)
It inflicts 2d5 (bonus) acid damage on hit
It grants acid immunity
It has a chance to paralyze opponents (say, 15%)
It is an artifact
Scathing scourge "The slave's master" {Ch - 99} (+19, 1d19 - 1) (19s) (one-handed)
It causes nearby NPC's to flee (like unholy aura)
It is permanently cursed
It decreases the energy cost of attacking by 40% when wielded
It (always) inflicts bleeding wounds on succesful hits
(another take on dual-wielding whips, maybe...)
hefty wet towel Hitchhiker's Hope {Ch + 7} (+7, 1d7+7) (7s) [+7, +0] (2-handed whip)
When unequipped or dropped, it is destroyed
Upon entering D:50, if it is not equipped, it is destroyed
When equipped while entering the chaos gate, an alternative ending is triggered: the chaos in the chaos realm triggers the chance of a spaceship flying by, and the character is taken on an interstellar journey. If lawful, the aliens eliminate Andor Drakon before leaving. If neutral, the gate is eliminated instead. If chaotic, Andor Drakon joins the party.