I didn't put this in "troubleshooting" not sure if I should have or not.
You can select the effect when the monster is dead.
"death action" it's found on the object options of the character.
here's the issue. In testing my monster has:
"[1] Create Blood surface"
BUT ONLY a poison type appears. When my PC's stand on it they get poison.
HOWEVER, if I have the skill "Leach" and stand on it, I get healed...
Looks green and poisonous
death action "[1] Create Blood surface"
I may have already solved this.
I think* if you have Blood type as "none"
and the Death action type of Blood puddle.. it seems to default to poison.
make sure you have Blood type as "Blood"
might be the solution.. testing to see