Sylvan Komushroomo

The monster effect "When this card is flipped face-up: You can excavate up to 5 cards from the top of your Deck. If there are any Plant-Type monsters among the excavated cards, send all of them to the Graveyard. Place the remaining cards on the bottom of your Deck in any order" is a Trigger Effect. (This effect does not target. It can also be activated during the Damage Step.)

When resolving the monster effect "You can excavate up to 5 cards from the top of your Deck," if there are any Plant-Type monsters among the excavated cards, the effect "If there are any Plant-Type monsters among the excavated cards, send all of them to the Graveyard" and the effect "Place the remaining cards on the bottom of your Deck in any order" are both performed. (If there are no Plant-Type monsters, only the effect "Place the remaining cards on the bottom of your Deck in any order" is performed.)

The monster effect "If this card is excavated from the Deck and sent to the Graveyard by a card effect: You can target 1 Spell/Trap Card on the field; destroy that target" is a Trigger Effect that activates in the Graveyard. (This effect targets 1 Spell/Trap Card on the field.)

The monster effect "You can target 1 Spell/Trap Card on the field; destroy that target" is an optional effect that can be activated if "Sylvan Staleon" itself is excavated from the Deck by a card effect and sent to the Graveyard by the resolution of that effect. (It can also be activated during the Damage Step.)