Tormentor's Helm
Artifact — Equipment
Equipped creature gets +1/+1.
Whenever equipped creature becomes blocked, it deals 1 damage to defending player.
Equip 
Zoltan Boros
Kaldheim (KHM)
• #155Rulings
The triggered ability triggers only once if the equipped creature becomes blocked, no matter how many creatures blocked it.
(wotc • 2021-02-05)
Rulings
The triggered ability triggers only once if the equipped creature becomes blocked, no matter how many creatures blocked it.
(wotc • 2021-02-05)