Limericks are humorous 5 line poems with a specific rhythmic pattern and an aabba rhyme scheme. What limericks consist of are generally created to make someone laugh hopefully. Or could it could be an annoying poem that someone gets tired of, but it usually depends on the reader.
There was an Old Man with a beard,
Who said, 'It is just as I feared!
Two Owls and a Hen,
Four Larks and a Wren,
Have all built their nests in my beard!'