“Burning Algae”’s effect activates when sent to the Graveyard from the field, your hand, or your Deck.
“Burning Algae”’s effect activates in the Graveyard, so when a face-down “Burning Algae” is sent to the Graveyard, or “Burning Algae” in your opponent’s hand is sent to your Graveyard, the effect is activated.
“Burning Algae”’s effect cannot be negated by “Skill Drain”.
When you Tribute “Burning Algae” to Tribute Summon “Dark Magician of Chaos”, “Burning Algae”’s effect is Step 1 of a chain and “Dark Magician of Chaos”’ effect is Step 2.