Combos with Undercover Operative

1. Cast Undercover Operative by paying its mana cost, choosing to have it enter the battlefield as a copy of Felidar Guardian
2. When Undercover Operative enters the battlefield, it triggers, blinking Felidar Guardian.
3. When Felidar Guardian enters the battlefield, it triggers, blinking Undercover Operative. Choose to have Undercover Operative enter the battlefield as a copy of Felidar Guardian.
4. Repeat from step 2.

1. Cast Undercover Operative by paying its mana cost. Choose to have it enter as a copy of Princess Yue.
2. Put Undercover Operative into your graveyard due to the legend rule.
3. When Undercover Operative dies, it triggers, returning it from your graveyard to the battlefield as a land named Moon. Choose to have it enter as a copy of Wormfang Newt, gaining its abilities.
4. When Undercover Operative enters, its first ability triggers, exiling it.
5. When Undercover Operative leaves the battlefield, its second ability triggers, returning Undercover Operative from exile to the battlefield. Choose to have it enter as a copy of Princess Yue.
6. Repeat from step 2.

1. Activate Kiki-Jiki by tapping it, creating a token copy of Undercover Operative that has haste. Choose to have Undercover Operative enter as a copy of Kiki-Jiki.
2. Put the oldest Kiki-Jiki into the graveyard due to the legend rule.
3. Repeat step 1 using the Undercover Operative token instead.

1. Cast Undercover Operative by paying its mana cost, choosing to have it enter the battlefield as a copy of Wispweaver Angel
2. When Undercover Operative enters the battlefield, it triggers, blinking Wispweaver Angel.
3. When Wispweaver Angel enters the battlefield, it triggers, blinking Undercover Operative. Choose to have Undercover Operative enter the battlefield as a copy of Wispweaver Angel.
4. Repeat from step 2.

1. Cast Undercover Operative by paying its mana cost, choosing to have it enter the battlefield as a copy of Abdel Adrian.
2. Put the original Abdel Adrian into your graveyard due to the legend rule, causing Karmic Guide to return to the battlefield from exile.
3. Karmic Guide and Undercover Operative's abilities trigger.
4. Resolve the Undercover Operative ability, choosing to exile Karmic Guide until Undercover Operative leaves the battlefield and creating a 1/1 Soldier creature token.
5. Resolve the Karmic Guide trigger, returning Abdel Adrian from your graveyard to the battlefield.
6. Put Undercover Operative into your graveyard due to the legend rule, causing Karmic Guide to return to the battlefield from exile.
7. Karmic Guide and Abdel Adrian's abilities trigger.
8. Resolve the Abdel Adrian ability, exiling Karmic Guide until Abdel Adrian leaves the battlefield and creating a 1/1 Soldier creature token.
9. Resolve the Karmic Guide trigger, returning Undercover Operative from your graveyard to the battlefield as a copy of Abdel Adrian.
10. Repeat from step 2.

Activate Undercover Operative by paying {1}{U}, shuffling Undercover Operative into your library and milling your entire library due to it not having a card named Mirror-Mad Phantasm in it.

1. Activate Kiora's Follower by tapping it, targeting Undercover Operative.
2. Illusionist's Bracers triggers, copying Kiora's Follower's ability.
3. Resolve both Kiora's Follower abilities, untapping Undercover Operative and another permanent you control.
4. Activate Undercover Operative by tapping it, untapping Kiora's Follower.
5. Repeat.

1. Cast Undercover Operative by paying its mana cost. Choose to have it enter as a copy of Anticausal Vestige.
2. When Undercover Operative enters, Cloudstone Curio triggers, returning Anticausal Vestige from the battlefield to your hand.
3. When Anticausal Vestige leaves the battlefield, it triggers, causing you to draw a card and and put Anticausal Vestige from your hand onto the battlefield.
4. When Anticausal Vestige enters, Cloudstone Curio triggers, returning Undercover Operative from the battlefield to your hand.
5. When Undercover Operative leaves the battlefield, it triggers, causing you to draw a card and put Undercover Operative from your hand onto the battlefield as a copy of Anticausal Vestige.
6. Repeat from step 2.

1. Activate Kiora's Follower by tapping it, targeting Undercover Operative.
2. Deeproot Pilgrimage triggers, creating a 1/1 Merfolk creature token.
3. Resolve the Kiora's Follower ability, untapping Undercover Operative.
4. Activate Undercover Operative by tapping it, targeting Kiora's Follower.
5. Deeproot Pilgrimage triggers, creating a 1/1 Merfolk creature token.
6. Resolve the Undercover Operative ability, untapping Kiora's Follower.
7. Repeat.

1. Cast Undercover Operative by paying its mana cost, choosing to have it enter the battlefield as a copy of Bladewing.
2. Put Bladewing into your graveyard due to the legend rule.
3. Undercover Operative's enter-the-battlefield ability triggers, returning Bladewing from your graveyard to the battlefield.
4. Put Bladewing into your graveyard due to the legend rule.
5. Bladewing's enter-the-battlefield ability triggers, returning it from your graveyard to the battlefield.
6. Repeat from step 4.

1. Cast Undercover Operative by paying {2}{U}{U}, choosing to have it enter the battlefield as a copy of Enduring Scalelord.
2. Undercover Operative enters the battlefield, triggering Cathars' Crusade, putting a +1/+1 counter on each creature you control.
3. Enduring Scalelord and Undercover Operative triggers.
4. Resolve the Undercover Operative trigger, putting a +1/+1 counter on itself.
5. Enduring Scalelord triggers, putting a +1/+1 counter on itself.
6. Repeat from step 4.

1. Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Undercover Operative.
2. Hapatra triggers, creating a creature token.
3. Activate Undercover Operative by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
4. Hapatra triggers, creating a creature token.
5. Repeat.

1. Activate Grim Poppet by removing a -1/-1 counter from it, putting a -1/-1 counter on Undercover Operative.
2. Nest of Scarabs triggers, creating a creature token.
3. Activate Undercover Operative by removing a -1/-1 counter from it, putting a -1/-1 counter on Grim Poppet.
4. Nest of Scarabs triggers, creating a creature token.
5. Repeat.

1. Activate Forensic Researcher by tapping it, targeting Undercover Operative.
2. Deeproot Pilgrimage triggers, creating a 1/1 Merfolk creature token.
3. Resolve the Forensic Researcher ability, untapping Undercover Operative.
4. Activate Undercover Operative by tapping it, targeting Forensic Researcher.
5. Deeproot Pilgrimage triggers, creating a 1/1 Merfolk creature token.
6. Resolve the Undercover Operative ability, untapping Forensic Researcher.
7. Repeat.

1. Cast Chronomantic Escape by paying {4}{W}{W}, causing creatures to be unable to attack you until your next turn, and putting Chronomantic Escape into exile with three time counters on it.
2. At the beginning of your postcombat main phase, both copies of Sphinx of the Second Sun trigger, causing you to get two additional beginning phases after this phase.
3. Move to your first additional beginning phase.
4. At the beginning of your upkeep, Chronomantic Escape triggers, removing a time counter from itself.
5. Repeat from step 3 one additional time.
6. At the beginning of your next upkeep, Chronomantic Escape triggers, removing a time counter from itself and causing you to cast it without paying its mana cost.
7. Resolve Chronomantic Escape, causing creatures to be unable to attack you until your next turn, and putting Chronomantic Escape into exile with three time counters on it.
8. Repeat from step 2.