Flitting Guerrilla — ruling 1

The triggered ability of Flitting Guerrilla triggers and goes on the stack without a target. If you exile Flitting Guerrilla, the second "reflexive" triggered ability will trigger. You'll choose the target creature or battle card for that second ability at that time. You may choose a card you just milled as the target or a card that was already in your graveyard.

Flitting Guerrilla : règles, fonctionnement et interactions (MTG)

Flitting Guerrilla is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Flying When this creature dies, each player mills two cards. Then you may exile this card. When you do, put target creature or battle card from your graveyard on top of your library. (To mill two cards, a player puts the top two cards of their library into their graveyard.)

How it works : Flitting Guerrilla

Original English text — Wizards of the Coast / Scryfall

#1April 14, 2023· Wizards of the Coast
The triggered ability of Flitting Guerrilla triggers and goes on the stack without a target. If you exile Flitting Guerrilla, the second "reflexive" triggered ability will trigger. You'll choose the target creature or battle card for that second ability at that time. You may choose a card you just milled as the target or a card that was already in your graveyard.
No other card is named in this ruling.