2 Feb 2024
Unruly Krasis's second ability will overwrite any previous effects that set the creature's power and toughness to specific numbers. Effects that otherwise modify its power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters.
2 Feb 2024
You can always activate an ability that will cause a creature to adapt. As that ability resolves, if the creature has a +1/+1 counter on it for any reason, you simply won't put any +1/+1 counters on it.
2 Feb 2024
The value of X is determined only once, as Unruly Krasis's second ability resolves. Further changes to Unruly Krasis's power that turn won't cause the target creature's base power and toughness to change.
2 Feb 2024
If a creature somehow loses all of its +1/+1 counters, it can adapt again and get more +1/+1 counters.