Hm I wonder if he DOES try to give them poison and plague will they get it. I mean those are his attributes so a spider would be good cause it can "stealth" kill people and the dogs can also spread plagues with the bites. I see some good foreshadowing with the past 2-3 chapters. In really looking forwards to this. Love the story. Keep up the amazing work. And you have my SS everyday.
If he can create any skeleton if he studies the creature bones it would be good in the long run even if it takes more time afterwards, like dragons and other creatures, but i still think a toxic, plague elemental would be better, you can't even touch or get near them(probably)
Jackel