So *this* is Don Thousand’s influence.

20AP-JP058  ドン・サウザンドの契約 Don Thousand no Keiyaku / Contract with Don Thousand
Continuous Spell Card
You can only activate 1 “Contract with Don Thousand” per turn.
(1) When this card is activated: Each player loses 1000 LP, also each player draws 1 card.
(2) Each player reveals, and keeps revealing, every card drawn while this card is in the Spell & Trap Zone, as well as every card drawn by this card’s (1)st effect.
(3) Each player revealing a Spell Card(s) because of this card’s effect cannot Normal Summon/Set monsters.

Source