Black Widow is a Negamonster sent by Neflite to gather energy for the Negaverse. She has the appearance of a spider. She attacks with spiderlike threads. She appeared in Sailor Moon episode 13, Wedding Day Blues.
Her essence was implanted in the wedding dress material picked by Miss Lambert, the sewing teacher. When her energy reached its highest point, Black Widow appeared and began draining energy. She fought Sailor Moon and trapped her with spider threads, but Sailor Mercury and Sailor Mars arrived and used Mercury Bubbles Blast and Mars Fire Ignite to confuse Black Widow and release Sailor Moon from her attack. Sailor Moon destroyed Black Widow with Moon Tiara Magic.