How do you easily troll a griefer? I will tell you how.

1. Place something valuable like a diamond block in a random house
2. Place pressure plates (stone on stone, wood on wood) like this around your diamond block
X=plate O=no plate D=diamond block
XOXOXOXOXOXOX
OXOXOXOXOXOXO
XOXOXOXOXOXOX
OXOXOXOXOXOXO
XOXOXODOXOXOX
OXOXOXOXOXOXO
XOXOXOXOXOXOX
OXOXOXOXOXOXO
XOXOXOXOXOXOX
3. Place redstone under all of the pressure plates and pistons under all of the blank spaces around you plates.
4. Make sure your house has no roof or a really high one or for fun, a lava roof!
5. The griefer will be shot into the air, and they will die on fall if you have no roof.
6. You have trolled a griefer!

Note: This may not always work if the griefer is a hacker.