A potion which would cause all close by NPC's to be aggressive toward you for a duration.

PROS:
-Would be fluid on market
-Would help overcrowding in popular spots (Lev 2/3 Rats, 5 Thugs, Ice Warriors/Giants)
-Dev could use to push players into unused areas/aspects of the game

CONS:
-Could potentially upset PKers by reducing number of trainers in Wildy
(i mean who doesn't like pking iron helms)

Whether training your main or a PKer, who doesn't love AFK training?
I feel this potion has a lot of appeal because it will still be useful to players even after they max out a main account. (training up pker, collecting resources,etc)

Devs could use this to push people into various parts of the game they feel are ignored, or find a way to incorporate it with new, low-to-mid-level players. You could do something like add an item to certain NPC's drops, let's say an eye for instance. A rat's eye, goblin's eye, and pirate's eye could be used with a Tarromin or Harralander to make the regular Aggression Potion, whereas a lesser demon's eye, *insert higher-leveled NPC here*'s eye could be used with a Dwarf Weed or Torstol to make a Super Aggression Potion. Each dose of regular would give three minutes of aggression, each dose of Super would give five minutes of aggression.  Hell, if the dev finds it funny, make people chase around imps or spiders. If someone doesn't want to be bothered with herblaw, they'll have something to sell that might actually move on the market. Or you could make the secondary something people have to do in an ignored skill, say woodcutting.  Lower-tiered trees could have a small chance to drop a crushed bird's nest for regular pots, whereas higher-tiered trees could have a small chance to drop bird's nest for Super pots. Maybe the nests have to be crafted first, or maybe the potion after it's made has to be blessed on a Zammy Altar with a low and high pray req. Just some ideas, options are endless I'm sure.

PLACES I'D LIKE TO DRINK ONE OF THESE BAD BOYS:
-Dark Wizards' Tower, snatching up the runes I want every few minutes
- Entrana, snatching up unicorn horns every few minutes
-Asgarnian Ice Dungeon, snatching up limpwurts every few minutes
-Make Over Mage's hut, I hate that dude's outfit

Hopefully I'm not alone... I'd buy them!