This has been an amusing thought in my head for some time. The idea is that the quest-giver, probably at some starter zone, is missing their cat. They escaped and have been roaming the town/city and hunting the natural wildlife (as well as potentially endangering itself to other creatures and enemies). So you have to go and catch the cat. The main objective could be to use some sort of trap to capture the cat - which could be reusable in later quests against other creatures, possibly with better traps - or to just pummel an overly-aggressive housecat and then have to explain to the quest-giver why their cat was roughed up. My idea behind trapping is that the trap may be placed randomly on the map or in a specific zone. You then have to tactically chase whatever mob into the trap. You may then pick it up in your inventory as an item called "Trapped [mob name]". Naturally, this would be what you bring back to whichever NPC to complete the quest objective.