When this card is Normal Summoned: You can send 1 Zombie monster from your Deck to the GY. If this face-up card in its owner's control leaves the field because of an opponent's card effect: You can Special Summon 1 Level 4 or lower Zombie monster from your Deck, except "Samurai Skull".
Activates upon Normal Summon, Sends from your Deck to your Graveyard
Special Summons from your Deck
Anonymous 23days ago
Thought I'd mention an interesting scenario (no official ruling on yugioh wikia though, just by observation). If Samurai Skull has been returned to the deck by Drowning Mirror Force, it is not considered to have "left the field by the opponent's card effect", and its effect doesn't activate.