Ghasts are undead souls of people that starved to death in Mort Myre swamp. When they first appear they are invisible and have no combat level, and try to turn food into useless rotten food; if players have no food they will do damage instead.
Ghasts can only be killed after completion of the Nature Spirit quest. You must have a Druid pouch and blessed silver sickle to kill them. You must use the ability of the blessed silver sickle near some dead logs or bushes to harvest Mort myre fungi, Mort myre stems, or Mort Myre Pears then put those into a druid pouch by filling it. When your druid pouch has been filled, you can use it to make a Ghast visible, or wait until a Ghast attacks you to make it visible. This renders the Ghast vulnerable to attack; killing it rewards the player with 30 Prayer experience.
Ghast hunting notes
Due to the nature of making the Ghasts visible, they are not good for combat training. They do drop lots of herbs, but so do Hobgoblins. The material drops are pretty weak as well. You do, however, gain reasonable Prayer XP as well as Combat XP for killing them.
The best place to hunt them would be just west of the Nature Grotto from the Nature Spirit quest. This allows you to keep refreshing your prayer points without using valuable prayer potions. The silver sickle does not have to actually be equipped to gain its benefits, it just has to be in your inventory. A player can use whichever weapon they choose for combat, not having to use the sickle. Fully charge your prayer points, go west of the Grotto (where the Ghasts are) and cast Bloom with the sickle next to the rotten logs. Try and do it between 2 logs, and you will occasionally get 2 mushrooms to put in the Druid pouch. Do this over and over until you are out of prayer points. Now "use" the filled pouch on the ghostly Ghasts - do not wait for them to attack you. Often they will just float around, or the pouch will activate itself, allowing the solid Ghast to float out over the water where it cannot be attacked. The drops will more often than not fall under the rotten logs, so search the ground carefully after defeating the Ghast.
You can actually fill the druid pouch much faster if you cast bloom near fallen tree branches, their trimmings count for 2 in your druid pouch as opposed to mushrooms only counting for one charge.
Weapons and armour
Item Quantity Rarity GE market price Iron dagger 1 Common 3 Iron mace 1 Common 12 Bronze kiteshield 1 Uncommon 26
Item Quantity Rarity GE market price Grimy guam leaf 1 Common 17 Grimy marrentill 1 Common 15 Grimy tarromin 1 Common 170 Grimy harralander 1 Common 827 Grimy ranarr weed 1 Uncommon 7,641 Grimy irit leaf 1 Uncommon 833 Grimy avantoe 1 Uncommon 1,492 Grimy kwuarm 1 Uncommon 1,175 Grimy cadantine 1 Rare 1,349 Grimy lantadyme 1 Rare 1,161 Grimy dwarf weed 1 Rare 626
Runes and talismans
Item Quantity Rarity GE market price Body rune 1–3 Common 5–15 Air rune 1–3 Common 5–15 Fire rune 7 Uncommon 35 Chaos rune 4 Uncommon 400 Cosmic rune 2 Rare 262
Item Quantity Rarity GE market price Coins 1–125 Common Not sold Fishing bait 7 Common 28 Tin ore 1 Rare 35 Eye of newt 1 Uncommon 4 Tinderbox 1 Uncommon 83
Gem drop table
In addition to the drops above, this monster has access to the gem drop table.
Show/hide gem drop table Item Quantity Rarity GE market price Uncut sapphire 1 Rare 702 Uncut emerald 1 Rare 826 Uncut ruby 1 Rare 1,488 Nature talisman 1 Very rare 851 Uncut diamond 1 Very rare 2,794 Rune javelin 5 Very rare 815 Loop half of key 1 Very rare 9,508 Tooth half of key 1 Very rare 12,240 Rune spear 1 Very rare 12,082 Shield left half 1 Very rare 65,684 Dragon spear 1 Very rare 38,429