If I copy a Walking Ballista with an Altered Ego, how many counters do I have? X, or 2 times X?

Hi,

That's covered by this rule:

107.3h Normally, all instances of X on an object have the same value at any given time. If an object gains an ability, the value of X within that ability is the value defined by that ability, or 0 if that ability doesn’t define a value of X.

The Ego Ballista will enter the battlefield with X counters on it (where X is determined by the X you selected when you cast the Ego), not twice X.

Nathan Long
Magic Rules NetRep