Cannot advice an object instance

[anodynos]

I would like to advice a single Object instance (that is perhaps created by a Function via new).
So if I have

class Blender
  doIt:->

this works fine

YADC(Blender).before(...)

but this doesn't

myBlender = new Blender()
YADC(myBlender).before(...)

I would like to advice ONLY the object at hand, and not the prototype. Is this too much to ask ?
My main pain is that my instance is extended after creation, with methods not known at the creator Function / class definition.