Groundling Pouncer — ruling 1

It matters that an opponent controls a creature with flying only as you activate this ability. Once you've activated it, Groundling Pouncer will still get +1/+3 and gain flying, even if all of your opponents' creatures with flying leave the battlefield in response to the ability or after the ability resolves.

Groundling Pouncer : règles, fonctionnement et interactions (MTG)

Groundling Pouncer 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

: This creature gets +1/+3 and gains flying until end of turn. Activate only once each turn and only if an opponent controls a creature with flying.

How it works : Groundling Pouncer

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
It matters that an opponent controls a creature with flying only as you activate this ability. Once you've activated it, Groundling Pouncer will still get +1/+3 and gain flying, even if all of your opponents' creatures with flying leave the battlefield in response to the ability or after the ability resolves.
No other card is named in this ruling.