How can anyone look at a plush toy without mirth? One has to be realistic with the subject material when attempting to change it's widely perceived appearence. Can Chucky the toy ever be made to look friendly without us imagining it murderous? Angry bird though created to look angry, will always be "funny" or "a fun game". This is a real plush toy and not computer generated graphics where you can change it's appearence to suit your purposes. Hence you need to push for maximum effect, push hard enough and maybe people can for a split second, forget what it is. And people will always react differently; some will forever see it as funny, others can see it for what you intend it to be. Overall I don't know how much can be done, quite a coup if you can.
There are big technical differences between what you want to achieve and the reality of it. How light falls on the human face and how light falls on a smooth round plush toy is obviously not the same. You just cannot switch the latter in for the former. That said, lighting for the plushie should follow the Godfather poster. Top down from the side, and never frontal lit. Add a back light for highlight. I understand you are working in limited resources and some of the most useful and cheap tools in studio photography, are lighting modifers & cards. Controlling lights via direction and ratio is the first step, shaping light to suit the purpose is the 2nd.
Modifers like tracing paper or white silk cloth for diffusing the light, DIY cardboard cones for focusing the spread of light.
Cards like white or black, both can act either as bounce cards (reflect light) or flags (blocking light).
As you can't change anything on the plush toy itself (or if you want to poke one of its eye and add fake blood), composition & lighting will have to carry its weight.
Composition-wise, I think you should begin by showing less. Turn it on its side profile and modify the light to just show its eye and nose for a start and work slowly from there. Or you can start by shooting it as a silhouette then gradually turning it and lighting bit by bit. Use the modifiers to help shape the light. Even if it doesn't work out in the end, it's still a very very useful exercise about learning product lighting. Good luck and have lots of fun!
