I am not sure what you are thinking will happen here. The Ego enters as a 6/6 Goliath with as many counters as was chosen for X. This causes their Goliath to trigger to get more counters. The process ends there. So, if the original Goliath had 3 counters already, and X was set to 2, the Ego/Goliath enters with 2 counters so it is an 8/8. The original Goliath gets 8 more counters which puts it up to 11 counters. Now, there is the original Goliath which is a 17/17 due to the counters and the new one which is still an 8/8.
Counters are not copiable so the Ego won't get any of the counters the original had and it doesn't keep changing if the source keeps changing. It takes a "snapshot" of what it is copying and it won't change from that if the original changes after.
Also, as a side note, there is never "infinite" in Magic. There is always a number.
Hamletback Goliath
Altered Ego
I am not sure what you are thinking will happen here. The Ego enters as a 6/6 Goliath with as many counters as was chosen for X. This causes their Goliath to trigger to get more counters. The process ends there. So, if the original Goliath had 3 counters already, and X was set to 2, the Ego/Goliath enters with 2 counters so it is an 8/8. The original Goliath gets 8 more counters which puts it up to 11 counters. Now, there is the original Goliath which is a 17/17 due to the counters and the new one which is still an 8/8.
Counters are not copiable so the Ego won't get any of the counters the original had and it doesn't keep changing if the source keeps changing. It takes a "snapshot" of what it is copying and it won't change from that if the original changes after.
Also, as a side note, there is never "infinite" in Magic. There is always a number.