Proboscis

A Proboscis is a stackable item that members can use (along with a spirit shard ,a gold charm, and an empty pouch) to make Spirit mosquito pouches as part of the Summoning skill. These pouches are used to summon Spirit mosquitos, which require level 17 Summoning.

Players completing Fairytale I - Growing Pains may need this item as a randomly selected item that they must take to Malignius Mortifer in order to make the magic secateurs.

Players can obtain proboscises from Mosquito Swarms, which drop a varying number of them during the Tai Bwo Wannai Cleanup minigame.

Before the Summoning skill was released, the proboscis had no purpose at all, and therefore, was available for about 2 coins.

This is also one of the few stackable tertiary ingredients in summoning, which may explain its high price. You could theoretically, with enough shards, charms, pouches, and probosci, get from level 17 to 99 in a single trip to the obelisk. However, to do this you would need 280,244 spirit shards, equating to 7,006,100 coins. Plus 280,244 probosci, equating to 904,907,876 coins. And 280,244 pouches, worth 280,244 coins. All of this to a grand total of: 912,194,220 coins, or 912.194 million coins. Being untradable, all 280,244 charms would need to be acquired manually. This theory is also just academic, because the finished pouches are not stackable and while you might have enough 'ingredients' each trip, you can only make 25 at a time before offloading the finished pouches into a bank.

Players can also get them as a reward from Soul Wars by using the "Gamble" option. Player can get them in quantities of 12.

Trivia
Proboscis used to have a different examine; "A giant mosquito's proboscis: aerodynamic, sharp and not very useful!" It was changed to what it is today after the release of Summoning batch 2 along with the Spirit mosquito familiar.