To trick, to impose on, to dupe.
A companion.
To dupe in a friendly manner for amusement; to mess with, play with.
To do or say something for amusement rather than seriously.
An amusing story.
The root cause or main issue, especially an unexpected one
A laughably worthless thing or person; a sham.
Something that is far easier or far less challenging than expected.
Something said or done for amusement, not in seriousness.