Warning: These pranks are not for the faint of heart.
Conceal all your sibling's socks. Place them in various hiding spots around the house. When they notice, act as if you've never seen them beforeæk.
Draw fake spiders on your sibling's wall with a piece of dry-erase marker. Wait for their reaction.
Switch all the furniture in your sibling's room with its mirror image. Watch as they try to navigate the inverted world.