I chose horse sized duck.
My reasons:
Why would an oversized duck or a 100 dwarfed horses exist and be out to kill / eat you in the first place ?
It can only mean someone is using witchcraft / blood magic to get rid of you, and assuming worst, those animals are most likely very well capable of doing the above.
Imagine a 100 little angry horses gnawing at your ankles. Their existence is unnatural. Meaning they are probably not weaker than if they were original size, ergo they are demonic and possibly even more aggressive and bitey, also you wouldn't be able to outrun them. Maybe climb on top of a roof / tree and just pick them one by one if you can find a weapon. I assume they can't fly .... That's still a 100 unnatural problems you prob wouldn't survive to begin with simply because they'd overrun you.
The duck be just one problem. Yes it could probably snap your head off with a single lunge/bite, but it's big, thicc and would struggle to get through a door frame. While stuck there you could just take a sharp / solid object and keep bashing its head in or working on it's neck till it's decapitated.
Does that make any sense ? ^^