After reading the entry for Shape Flesh I'm a little puzzled. I'm still a pretty new Dark Heresy player, but my Psyker's about to hit rank 4. As I was going to go into Biomancy I'm a little curious about how far Shape Flesh can be taken.
There don't seem to be a whole lot of limitations to it, in particular the description of the ability and the bit that states the Psyker can take the appearance of a creature.
In particular does this apply to size? If my Psyker, for example, wanted to infiltrate a structure and thus tried to take the form of an owl (or some form of avian creature), would his size naturally adjust or would he literally become a human-sized owl? Similarly, if, for combat, he wanted to become something much larger than a human for intimidation or the like (let's say a Grizzly Bear), would he end up transforming into just a very small bear?
I'm not the kind of person who likes powergaming, but at the same time, I do like to know how far I can take an ability.
Or is this sort of thing up to the GM's discretion?