Moltres Missingno?

When your phone is on drugs and everything makes no sense.

I've seen people on Reddit get these bugs where the pokemon turn into cubes just like yours did. Try fleeing and then re-entering the catch.

I had it with one of the quest reward pokemon. I ran from the encounter and restarted the app and it was fixed.

Catching a Missingno would be awesome. How many Rare Candies do you have now?

Just flee and come back, it worked for me.

I had it too, for both Moltres and a Meowth reward.
A friend also had it for his Moltres.

Both me and my friend use the same model of phone: One+5 (Android 8, Oxigen 5)

What game is that

You're not surfing on Cinnabar Island by any chance are you?