Mordenkainen's Polymorph
Instant
Until end of turn, target creature becomes a Dragon with base power and toughness 4/4 and gains flying. (It loses all other creature types.)
"Your purpose may change along with your shape, but you will serve regardless."
Oriana Menendez
Rulings
Mordenkainen's Polymorph will overwrite any previous effects that set the creature's power and toughness to specific values. Effects that otherwise modify the target creature's power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters.
(wotc • 2021-07-23)
The creature doesn't lose any of its abilities.
(wotc • 2021-07-23)
Rulings
Mordenkainen's Polymorph will overwrite any previous effects that set the creature's power and toughness to specific values. Effects that otherwise modify the target creature's power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters.
(wotc • 2021-07-23)
The creature doesn't lose any of its abilities.
(wotc • 2021-07-23)