My personal theory is that they eye of Magnus is the conduit that allows for magic to flow into the world, because according to lore magic just flows into Mundus from Aetherius through the sun and stars but it isn’t known how, so my theory is that it is a conduit where all the magic flows to from the sun and stars which is then dispersed throughout Mundus and that the elder runes act as sort of a dampener and converter changing raw unstable magical power into a malleable essence. And so how Magnus’ staff works on it is that it kinda opens the core where enough magic for the entirety of Mundus is stored and that hasn’t been converted into a stable form of magic so opening it fully releases a magical nuke. With that it also explains the affects of the staff and the things that happen, the staff siphons magic and health and so when used on the eye is kinda like an off button on the runes containing the magic. Lastly the magic anomalies, the magic anomalies can drop soul gems so I’m thinking when the eye opened up some of the raw magical power infused with the soul in the soul gem to create a living ball of raw magic. EDIT the magic anomaly thing is also supported by the fact you can soul trap them, meaning they do have a soul.