Scare someone this Halloween by making blood appear without cutting yourself! This is real science -the main ingredients are potassium thiocyanate and Ferric Nitrate. Push play or go to Metacafe. You can also consult the printed instructions. Link
While this trick does look uber cool, according to this website it may cause sever skin irritations! http://www.jtbaker.com/msds/englishhtml/p6181.htm http://www.jtbaker.com/msds/englishhtml/f1244.htm
Well obviously if they chemicals were dangerous they wouldn't put it on someone's arm, let alone advertise on the internet for everyone else to do it too.
Does it bother anyone that the person with the chemicals is wearing rubber gloves? They seem to be taking proper precautions, but in the next instant puts the potassium thiocyanate solution on someone's bare arms.
http://www.jtbaker.com/msds/englishhtml/p6181.htm
http://www.jtbaker.com/msds/englishhtml/f1244.htm
I still may try it though :/