Naturally, some Japanese characters are just naturally going to be more disgusting than others...
But I figured I was on to a winner with: 生殖
1st page, 7th result: http://www.chiba-muse.or.jp/UMIHAKU/kik
[Dude... Not nice.]
2nd page, 7th result: http://www.sci.ehime-u.ac.jp/bio/ev
[I'm really not a fan of close-up arthropod photos.]
12th page, 14th result: http://24hour.blogbus.com/files/1126118
[Nice birthday cakes... o_0;]
Oh... and as an additional bonus... for 腫瘍
At least half the results on the two pages are winners...
1st page, 6th result: http://www.geocities.co.jp/AnimalPark-T
[Snehe... thats... nasty. Nasty for the subject AND nasty for us.]
And when ALL RESULTS ARE SELECTED...
1st page, 13th result: http://oak-animal.com/shorei/case4/p
[I'm not sure whether to laugh or vomit.]
(For what its worth, 腫瘍 is supposed to mean 'tumour', which kinda speaks for itself.)