Bloodflies

"There's an egg in every bite, each secreting a poison that deadens, turns your flesh into something soft. And dead. Food for the larvae inside those eggs...those eggs are about to hatch, then the larvae will start eating you - from the inside out...the deadening poison kills the flesh. You'll heal, but there will be pockmarks...Normally, bloodflies don't swarm. It must have been the flames...someone with High Denul - can remove the scarring..."

Heboric
DG, UK MMPB, p.223-4

"'One drop, on your fingertip, then push that drop right into the wound, push it hard...The tincture, a foul, dark-brown juice that stained her skin yellow, did not kill the emerging larvae, but drove them out...each sluggishly wriggled free...each larva as long as a nail clipping, limp with the soporific effect of the tincture.'"

Heboric on treatment of bloodfly bites using a bitter tincture
DG, UK MMPB, p.223-4

'Rapid heart, chills, nausea. It's the juice of a plant native to Seven Cities. If you drank down what's left in that tiny bottle you'd be dead in minutes'

The side-effects of the bloodfly tincture
DG, UK MMPB, p.224