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Someone tried to play the following combo in a game I was in. I think it is an illegal play, so I wanted some help to clarify the rules.
The cards were:
1) Launch Party - "As an additional cost to cast Launch Party, sacrifice a creature."
2) Mogg Fanatic - "Sacrifice Mogg Fanatic: Mogg Fanatic deals 1 damage to target creature or player."
The other player played Launch Party and wanted to sacrifice Mogg Fanatic to pay Launch Party's cost. However, they also wanted to benefit from Mogg Fanatic's own ability.
This doesn't seem legitimate, because it would be a "two for one" (pay one cost, get two spells). Am I correct?