Sorcerer's Wand
Artifact — Equipment
Equipped creature has "
: This creature deals 1 damage to target player or planeswalker. If this creature is a Wizard, it deals 2 damage instead."
Equip 
Matt Stewart
Dominaria (DOM)
• #231Rulings
Whether the equipped creature is a Wizard is checked only as the ability resolves. If that creature has left the battlefield, use its last known information to determine if it was a Wizard.
(wotc • 2018-04-27)
The equipped creature, not Sorcerer’s Wand, is the source of the damage-dealing ability and of the damage dealt.
(wotc • 2018-04-27)
Rulings
Whether the equipped creature is a Wizard is checked only as the ability resolves. If that creature has left the battlefield, use its last known information to determine if it was a Wizard.
(wotc • 2018-04-27)
The equipped creature, not Sorcerer’s Wand, is the source of the damage-dealing ability and of the damage dealt.
(wotc • 2018-04-27)