Here's what happened:
* Ichigo's Hollowfication: This occurred when Ichigo's inner hollow, a powerful spirit entity that coexisted within him, briefly took control. This was triggered by his immense anger and desperation after the death of his friend, Rukia Kuchiki.
* His Power and Control: While Ichigo had glimpses of his hollow power and gained a boost in strength, he managed to maintain control and overcome the influence of the hollow.
* No Subsequent Hollowfication: Throughout the series, Ichigo never underwent a similar hollowfication experience. He learned to harness his inner hollow's power without losing control, but he did not become a full-fledged hollow.
So, while Ichigo's initial hollowfication was a significant turning point in the series, he never experienced a second time.