One thing that I found particularly odd in the "His Dark Materials" trilogy is why none of the demons, while they're still capable of changing forms, never assume a useful form like a lion (which does happen for some people in the books), a snow Leopard (like Lord Asriel's dæmon), a bear, etc.
It seems there are multiple instances where the cruel golden monkey dæmon of Marissa Coulter either apprehends Lyra or her demon, and torments them via physical torture. In the third book, Pantalaimon even turns into a porcupine briefly to prick the monkey with quills, and in the first book he turns into a crow and convinces other children's dæmons to do the same to help their humans. So, it's apparent he has a considerable degree of control over the form he assumes.
It is made obvious by the second book that Lyra hates Marissa, and has already uttered death threats to people she hates. I've always wondered why Pantalaimon didn't just change into a jaguar and tear open the golden monkey. It would save him, kill Marissa, and simplify their entire mission. The same applies to when the Tartar pulled Lyra from the vents in the first book. He even broke the taboo of not touching other people's dæmons.
What would best explain this? It just feels like an oversight of the author more than anything else.