There was once a small brown fish
That didn't want to be put on the dish.
So it was put in the acquarium
And transported to the oceanarium-
Now sharks hunt this fish as it wished.
A limerick is a form of verse, usually humorous and frequently rude, in five-line, predominantly anapestic[2] meter with a strict rhyme scheme of AABBA, in which the first, second and fifth line rhyme, while the third and fourth lines are shorter and share a different rhyme.
(https://en.wikipedia.org/wiki/Limerick_(poetry))