Souls
Rattleshakes do not have souls in the traditional sense. Rather, their core liquid serves as their soul, influencing their personalities, abilities, etc. Despite this fact, it is not correct to call them soulless. They still possess an essence, a culmination of being, it is simply in a liquid form. (See Cores for more information).
Attacks
Shakes are able to summon attacks, though they do tend to be smaller and less powerful than that of a typical skeleton. All have some form of basic bone projectile, accompanied by a special ability. These abilities come in many forms, from strings, to projectiles, to summoning additional appendages, and are almost always related in some way to their core liquid.
For those with poisonous cores, their attacks will have a similar affect to their contents if they manage to enter the bloodstream/system of those they are leveled against. Those with potion cores will find their attacks are likely to imbue their magical properties, for example getting hit with an attack from a shake with a potion of levetation core will make one float.
Extracting Core Liquid
Rattles are able to summon the liquid from their core and manipulate it. This is very rarely done as extracting too much will leave a rattle feeling weak, and is usually done in small quantities for the purpose of filling eggs or in the case of ve-noms to use poison in different ways. The liquid will float in bubbles and streams directed by the individual, and can be reabsorbed by them as long as they do not release their hold on it.
If core liquid is sullied while extracted then reabsorbed, for example if it picks up particles such as dirt and debris, reabsorbing it can make the rattle sick. While the body will naturally work to filtre out such things in small quantities, its hard work and exhausts it much like fighting off foreign invaders such as germs would. This differs from naturally occurring complements to the liquid core (see Toppings).
Healing Magic
Monster food and drink is imbued with magic and tends to by nature have healing properties. For this reason, snake bites and sip-ents tend to have a natural talent for healing magic. Some will have more of a knack for it than others, just like some foods and drinks grant more or less healing comparatively. Drinking the core liquid of a shake has a lot more potent healing effects than simply being healed by them or drinking the same liquid just as a standard monster food or drink. However, this is very ethically dubious for obvious reasons, and is generally considered taboo. This doesn't mean it doesn't happen in darker worlds though, and some rattleshakes have been known to even voluntarily sacrifice some of their liquid to the extremely ill or dying.
Rattleshake healing magic has less affect on other rattles as compared to normal monsters. The more different the liquid core of the other shake, the less affective the healing efforts will be. However, if there is a sufficient level of comparability (ie. the cores either match or would mix to form something meaningful) transplants are possible to restore depleted core liquid levels or heal serious injury. The introduction of foreign magic in significant quantities may affect the reciever's body. For example, if a lemonade rattleshake recieved a liquid transplant from an iced tea rattleshake, they may turn into an arnold palmer rattleshake and their appearance, bones and all, would be affected accordingly. Some cores are also just not compatible.
The subspecies that are the worst at healing are ve-noms, though vile vials tend to struggle with it as well. When your very essence is designed to hurt, even with the best of intentions, the poison will tend to seep into not just your attacks but your healing as well. For this reason, most ve-noms tend to turn to actual magical food to try and heal themselves and/or each other, for fear of doing more harm than good.
A ve-nom may recieve a transplant from a non-toxic core and suffer no ill affects, but a transplant of a ve-nom's core liquid will poison the reciever if they are not a ve-nom as well. If the receiver survives, their contents will be polluted and they will become a ve-nom as well. This can be very frightening for the recipient, as they may experience changes in their temperment and body, such as sharper teeth and temper, regardless of previous disposition.
Portals and AU Travel
Some shakes are able to travel through AUs, though most are not. Usually it’s more powerful individuals or those with specialized abilities or roles who possess this talent. Others grab rides on knowing or unknowing multiverse travelers or manage to get their hands on universe hopping tech. Not all will travel, some will remain in the same place all their lives, often not even knowing of the existence of other worlds.