Right, how do I punish ds(8) ?

[winnybella]

Just got off the phone with his teacher.
Apparently yesterday during recess he went up to his class. He had to go through the classroom adjacent to his was locked and in that class he:
Erased everything off the blackboard
Wrote on someone's exercise book 'teacher is an idiot'
Then in his class he hid other kid's books under a bookshelf
Took out of his teacher's desk's drawer an object she has confiscated from him earlier

When we were leaving school yesterday his friends were joking that he'll get spanked etc. When I asked him if he has done anything naughty, he made a big show of thinking about it and said 'no'.
Teacher told me that he had an audience with the headmaster yesterday. She also wrote me a note that he didn't show to me and lied today to the teacher saying that I saw it, just didn't sign it.
I posted before worrying about his lack of friends etc, but the teacher said today that he is 'transformed', has lots of friends now...
So, MNers, what course of action should I take? I'm thinking: a serious talk, no DS or tv til Friday night when he goes to his dad,and maybe an old-fashioned copying 20 times' I will not lie to my parents' or similar.
What would you do?

Definitely the serious talk. Definitely withdrawal of a privilege.

But maybe instead of lines, you could do what I did with ds1 a couple of weeks ago (although he's 14, but would still work).

I made him write out an apology to his teacher (Spanish teacher- he had refused to take part in two sections of his assessment) on a pretty card. I made him write it out in rough many times until I was happy with the presentation. Then I told him I would be speaking to his teacher to check that he'd handed it in to her. He was mortified but did what I said.

His behaviour (in that class at least) has been exemplary since then.