Sylvan Guardioak

The monster effect "Once per turn, during your Main Phase: You can excavate up to 3 cards from the top of your Deck" is an Ignition Effect. (This effect does not target.)

If there is a Plant-Type monster among the cards excavated by the monster effect "excavate up to 3 cards from the top of your Deck", the effect "if there is a Plant-Type monster among the excavated cards, send all of those cards to the Graveyard" and the effect "place the remaining cards on the bottom of the Deck in any order" are both applied. (If there are no Plant-Type monsters, only the effect "place the remaining cards on the bottom of the Deck in any order" is applied.)

The monster effect "If this card is excavated from the Deck and sent to the Graveyard by a card effect: You can target 1 Plant-Type monster in your Graveyard, except this card; place it on top of the Deck" is a Trigger Effect that activates in the Graveyard. (This effect targets 1 Plant-Type monster in your Graveyard, other than "Sylvan Oak" itself.)

The monster effect "You can target 1 Plant-Type monster in your Graveyard, except this card; place it on top of the Deck" is an optional effect that can be activated when "Sylvan Oak" itself is excavated from the Deck by a card effect and sent to the Graveyard as a result of that effect's resolution. (This effect can also be activated during the Damage Step.)