My 10mo has started headbutting the floor. I thought it was frustration at not being to reach toys etc, but he has started crawling now and is still doing it.
When he's tired he'll often start bashing himself on the head with a toy, but the headbutting seems to happen throughout the day. Could it be teething, as he has another 2 teeth coming through (has had 6 in the last 6 weeks).