This is in direct relation to: #28

Here is the feature plan for how mobs will work:

• Live render of mob when hovered on mob name in list
• A new Gui for adding mobs with a dynamic render of the mob you wish to add
• Logically a Outline of the whole mobs model would be the most logical thing to do to show the mob.
• Full Mod support
• A way to select mobs with specific meta
• Separate Radius to normal Xray
• Radius menu to display toggle options of [mobs, XRay, Caves]
• Add Icon for overlay

For the outline, you could "apply"the Glowing effect (similar to spectral arrows). I've seen it in this other mod (Hacker Voice: I'm In)

Hmm, I think I know what you mean, I don't want to add to much more to the render process but I think its a possibility.