I'm full of stench,
perhaps from a swamp,
just take a deep breath and
you'll not want to chomp.
Deadly am I, it is sure to see,
I have been controlled, still
don't go near me.
Magotts and flesh rotting ,
fill the air.
The damage I cause,
is too harmful too bare.
What am I? Only one word and please use the spoilers.