Dodecapodo

If a spell or ability an opponent controls causes you to choose a card to discard and you discard Dodecapod, you'll put it onto the battlefield.

If the spell or ability that caused you to discard Dodecapod refers to "the discarded card" or similar, it refers to the Dodecapod on the battlefield.

If you discard Dodecapod and put it onto the battlefield, you've still discarded it. Abilities that trigger whenever you discard a card will trigger.