I want to say:
It is
attempting to
drink sea water when you feel extremely thirsty, but doing it will only kill you.
Here by saying attempting to
I would like to emphasize the feeling that "can not refuse to try"... But I am not sure by using attempting
is the right word or right way.
attempting
in this way makes it seem you are reffering to another organism (it). Better is using something alike to what you said and taking out "is": It seems alright to drink sea water when you are extremely thirsty, but doing it will only kill you.