I forgot what sutta it was in the samyutta Nikaya by Bhikkhu Bodhi but I think it was the one where buddha warns the monks of 5 things a householder should watch out for, then he tell the monks that just like the householder should watch out for those 5 things a bhikkhu should watch out for these 5 things, waves, whirlpools, sharks and demons. Sharks meaning women. Ever since then I refer to woman as sharks because I'm afraid of sharks
Bhikkhu Bodhi mentions it when discussing various suttas. He says, 'This discourse was given at Catuma to the disciples of the Venerable Sariputta and the Venerable Maha Moggallana, who came with five hundred bhikkhus to see the Buddha. The five hundred bhikkhus made a lot of noise while settling down. The Buddha refused to see them at first, but later relented and taught them the dangers in the life of a bhikkhu. Just as there are dangers and hazards in a sea like stormy waves, crocodiles, whirlpools, and sharks, so also there are dangers against which the bhikkhu must be always on guard, namely, ill will against those who instruct them and guide them; dissatisfaction with training rules such as those concerning taking of meals or dealing with womenfolk; and pleasures of senses.''
The actual sutta (excerpt below) does not mention sharks, but rather refers to alligators. Catuma Sutta
..... Bhikkhus, what is the fear for alligators? . Bhikkhus, a certain son of a clansman out of faith goes forth from a household. He becomes a homeless thinking I'm overcome by birth, decay, death, grief, lament, unpleasantness, displeasure and distress. There are only a few who could declare the complete ending of this unpleasantness. He gone forth thus, putting on robes in the morning, taking bowl and robes goes the alms round, in the village or hamlet controlled in body and speech, mindfulness not established and mental faculties not protected. In the village he sees a woman not well covered and dressed. Seeing her in that manner, greed assails his mind and with a mind assailed by greed he gives up robes and becomes a layman. He gives up robes and becomes a layman out of fear for alligaters. Bhikkhus, fear for alligators is a synonymn for women.http://www.metta.lk/tipitaka/2Sutta-Pit ... ma-e1.html