It is the beginning of my upkeep, I pay W to turn my Glint Hawk Idol into a artifact creature, and place on it a +1/+1 using my Energy Chamber
when the turn ends and the idol stops being a creature, does the +1/+1 counter fall off?
It is the beginning of my upkeep, I pay W to turn my Glint Hawk Idol into a artifact creature, and place on it a +1/+1 using my Energy Chamber
when the turn ends and the idol stops being a creature, does the +1/+1 counter fall off?
No, because it never went on in the first place. You don't get the chance to turn the Idol into a creature before you choose a target for the Chamber's ability.
Fluttershy is best pony.
although if you did get a +1/+1 counter on the idol through some other means while it was a creature, it would say on it even when it ceases to be a creature