What happened to the old Gryffindor in Harry Potter and Stone Chamber of Secrets?

You're likely thinking of Nearly Headless Nick, the resident ghost of Gryffindor Tower. He is not an old Gryffindor, but rather a deceased Gryffindor student who was nearly beheaded, hence his name. He's actually a friendly and helpful character in the series.

It's important to note that Nearly Headless Nick is present throughout the Chamber of Secrets events and doesn't experience any specific happenings related to the Chamber. He does, however, play a small role in the story:

* He helps Harry: During the Chamber of Secrets' opening, Harry is confused and scared. Nearly Headless Nick tries to help Harry by giving him information about the Chamber and offering to accompany him. He ultimately fails to assist Harry directly, but he does play a crucial role in setting the tone for the plot.

* He's a source of humor: Nearly Headless Nick provides comedic relief with his quirky personality and tragic backstory, making him a unique and endearing character. He also contributes to the school's atmosphere and its overall sense of history.

So, while Nearly Headless Nick doesn't experience any significant events in the Chamber of Secrets, he is a constant presence in the story, both as a source of humor and as a reminder of the castle's history and the various mysteries it holds.