Skirk Marauder

Morph {2}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When this creature is turned face up, it deals 2 damage to any target.

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Archenemy

Morph {2}{R} (You may cast this face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Skirk Marauder is turned face up, it deals 2 damage to target creature or player.

Legions

Morph {2}{R} (You may play this face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Skirk Marauder is turned face up, it deals 2 damage to target creature or player.

Arena League 2003

The trigger occurs when you use the Morph ability to turn the card face up, or when an effect turns it face up. It will not trigger on being revealed or on leaving the battlefield.