the scenario you described would be considered leeching and if you can determine the person who is doing as such then they can and will most likely be jailed or banned or something.
in the case of anubis i'm not sure of a good way of countering something like this as i don't really know of a way to heal undeads, but for anything not undead, just get a vitata card and heal away then kill the monster yourself. granted this makes you use up extra resources, but it would ensure that all effort on part of the other individual was wasted.
