If it's entirely untypeable, the answer is always 'penis'.
(I'm not even being a troll - so many people must have caught the 4chan meme of doing this to captchas that they must filter for it by now, which means it's actually more likely to avoid giving them a false result than anything else you could put in.)
no subject
(I'm not even being a troll - so many people must have caught the 4chan meme of doing this to captchas that they must filter for it by now, which means it's actually more likely to avoid giving them a false result than anything else you could put in.)