I have a question, what is an haiku ?, i learned to this in school, but i didn't remember today

a haiku is a short non-rhyming poem comprising 3 lines - the first line has 5 syllables, the second 7, and the third 5.

as an example, here is the winning haiku from the last battle (the theme was "darkness"):

in-complete view, there
are fuzzy blanket layers
of vibrant static

by the way, it doesn't have to be in english.