Yugioh - Trickstar Lycoris + Dark Room of Nightmare?

Trickstar's exact wording is:

"Each time a card(s) is added to your opponent's hand, inflict 200 damage to them for each."

This means that a one-time damage is applied of 200*X, where X is the number of cards drawn.

So if your opponent plays Pot of Greed to draw two cards, they would take (400) damage from Lycoris, then Dark Room of Nightmare would activate, adding (300) damage.

If instead your opponent plays Heart of the Underdog and draws their 1st card in the draw phase, they'll take (200) damage from Lycoris, then (300) from Dark Room, then each time Heart of the Underdog allows them to draw a new card, the cycle repeats and they take (200) from Lycoris, then (300) from Dark Room.

So the key point is the "each time a card(s) is added", meaning Lycoris' effect only happens once, so Dark Room of Nightmare can't stack based on the number of cards drawn, only the number of occurances where cards are drawn.

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