

Q1: I used this card's On Play When Digivolving When Attacking effect to delete an opponent's Digimon with an On Deletion effect, and I used the part of the effect after "then" to return that card from their trash to the bottom of the deck. Can that deleted card's On Deletion effect activate at such times?
No, it can't be activated. When a card with an effect that's pending activation leaves its current area while activation is pending, the effect can no longer be activated. In this case, the deleted card's On Deletion effect triggers, but it's removed from the trash before the effect can activate.
Q2: What happens to cards placed face up in the security stack by effects?
They become face-up security cards that remain revealed. Other than rules that specify face-up security cards, the rules apply in the same manner as standard security cards.
Q3: What happens upon a security check for a security card that is placed face-up?
The check is performed with the card left revealed. Other than rules for cards left revealed, the rules apply in the same manner as standard security checks.
Q4: Does a card's Security effect trigger upon a security check with that card placed face-up?
Yes, it triggers.
Q5: What happens if I shuffle a security stack that includes security cards placed face-up?
Any face-up cards are placed face down, then you shuffle the cards. After shuffling, all cards are left face-down.
Lv.6 Phoenixmon BT23-015 U Mega | Vaccine | Holy Beast/Zaxon/CS When this card would be played, if you have a Tamer with the [Zaxon] trait, reduce the play cost by 5. [On Play] [When Digivolving] [When Attacking] [Once Per Turn] Delete 1 of your opponent's Digimon with 9000 DP or less. Then, you may return up to 3 non-Digi-Egg cards from their trash to the bottom of the deck. [On Deletion] Place this card face up as the bottom security card. ---
Lv.6 Phoenixmon BT23-015 U Mega | Vaccine | Holy Beast/Zaxon/CS [Digivolve] Lv.5 w/[CS] trait: Cost 3 When this card would be played, if you have a Tamer with the [Zaxon] trait, reduce the play cost by 5. [On Play] [When Digivolving] [When Attacking] [Once Per Turn] Delete 1 of your opponent's Digimon with 9000 DP or less. Then, you may return up to 3 non-Digi-Egg cards from their trash to the bottom of the deck. [On Deletion] Place this card face up as the bottom security card. --- -
Lv.6 Phoenixmon BT23-015 U mega | Vaccine | Holy Beast/Zaxon/CS [Digivolve] Lv.5 w/[CS] trait: Cost 3 When this card would be played, if you have a Tamer with the [Zaxon] trait, reduce the play cost by 5. [On Play] [When Digivolving] [When Attacking] [Once Per Turn] Delete 1 of your opponent's Digimon with 9000 DP or less. Then, you may return up to 3 non-Digi-Egg cards from their trash to the bottom of the deck. [On Deletion] Place this card face up as the bottom security card.
Lv.6 ホウオウモン BT23-015 U 究極体 | ワクチン種 | 聖獣型/ザクソン/CS このカードが登場するとき、特徴に「ザクソン」を持つ自分のテイマーがいるなら、支払う登場コスト-5。 【登場時】【進化時】【アタック時】[ターンに1回]DP9000以下の相手のデジモン1体を消滅させる。その後、相手のトラッシュから、デジタマカード以外のカード3枚までをデッキの下に戻せる。 【消滅時】このカードをセキュリティの下に表向きで置く。 ---