Do not ignore the behavior. It will only get worse. I like the idea of your coming to school to get him as a message that communication about this behavior is immediate between home and school. However, I caution that if you send dad each time, the message is that father is the disciplinarian only. Make sure you both play the role so that a united front is evident and so that neither parent is perceived as the villain.
Total isolation is recommended for a time frame appropriate to the child.
Start off with a shorter time and prolong the duration if and when more strident measures are necessary. Ignore all crying, screaming, etc. Do not tease. Do not lecture. Just be consistent.