Like any dangreous stuff you might breath in and anything that poses a real threat basically..
201925
The top concerns that come to my mind are Radon gas and mold/mildew if the basement is damp.  Both can be tested for if you are concerned.
550298
The bodies natural way to protect you from imminent danger.
310631
something that can destroy friendship,love and generally everything....
257835
To breath, anything involves fossil fueled vehicles, gas stoves, etc...
143500
Dont take the item out of the body, it will cause internal bleeding and possibly cause more damage than needed..
80612
Dude.... thats one scary-looking mug you have there\n\n:)
535780
Of course!\n\nA. Hold your breath, then drink a lot of water.\nB. Let someone scare you...scary, lol\nC. Go upside down and hold your breath\nD. Go upside down, drink water...WARNING, this can be dangerous.
574361
I BRLIEVE IT IS SOMETHING ON FEAR
87552
You are sure right - It can be pretty bad.
234391
The threats are disturbing.  Consult the police and be very very careful.  People like that carry out their threats.
580951
please see a doc sounds horrific and could be dangerous
277860
Sounds dangerous to me.
322535
your confusing fear with protection against evil my friend
419266
Very very dangerous. Potentially fatal.
71927
Stick your finger in your a** and scare it out!! :)
69655
I would be scared to death of it.
550636
What the hell do you want us to do about it? Call the police if you are that scared.