haiku again

A Haiku is a Japanese poem. It is very important to only put 5 syllables in the first sentence, and it is also very important to put 7 and 5 syllables in the next two sentences . I don't really know why  but it just has to and that's what i know. This is my haiku : Hides in the shadow 
and nimbly waits for a fly
they use fangs to eat 

 Beware