So for the sake of story one of my sims has to die, but I want the death to fit to the story therefore it can not be goofy like death by cowplant or too sudden like eating bad pufferfish. I like the ...
Do you have My First Pet Stuff? You could go with Rabid Rodent Fever. It’s slow and drawn out, it requires your sim to be quarantined or it will spread, very dramatic.