More kids tripping in lab coats
Atrophy.
Because he might fiddle with your kids.
The teacher was rather bewildered. "Don't you mean Michael " she asked. "No ma'am. I've written the 'M' already."
Student Funny, I was just going to ask you that.
Because they were Russian!
To trip ants.
Bring your own beer" Bill Nye the Science Guy slowly slides the bacteria sample back in his lab coat