Home-brew unique magic item

[Castiel1]

The First Reality; a sort of miniature earth, used when the deities were first creating reality, as a sort of, "So this is what I'm thinking it'll look like". This item is supposed to be a strong point in reality, almost impossible to damage, and also able to fix what has been shattered. So, the abilities:
The First Reality (legendary, requires attunement): While attuned, the creature can cast mending at will. The First Reality have 7 charges. As an action, you can cast: cure wounds (1 charge per level), lesser resoration (2 charges), mass healing word (3 charges), or greater restoration (5 charges). The First Reality regains 1d4+3 charges each day at dawn. Once per day as an action, you can attempt to cast invulnerability, with a duration of 2d4 rounds, no concentration. When you do so, you have a 30% chance to instead become paralysed for 1d4 rounds.

Looking to see whether the last ability, in particular, is over/underpowered.

[JNAProductions]

Seems pretty fine to me. Honestly, excepting the last bit, pretty weak for a Legendary item, and considering the last bit has a good chance of paralyzing you...

Yeah, I doubt it'll break anything.

[Ninja_Prawn]

My feeling is that it's underpowered for the legendary tier. It's basically a Staff of Healing (rare) with a slightly dodgy once/day invulnerability tacked on, and I certainly wouldn't choose it over a Staff of Fire or a Staff of Frost (both very rare). To sit among the legendary items, it needs to be on par with things like Apparatus of Kwalish, Luck Blades, Rings of Three Wishes, Cloaks and Rings of Invisibility, Staves of the Magi, etc.

I would say the Staff of the Magi is the best benchmark here. You're free to upscale this 'first reality' to that level without risk of it being overpowered.

[Castiel1]

Thanks for that, I haven't really played with the Invulnerability spell, so it's nice to know the item isn't overpowered, and may in fact be unpowered. I'll keep it legendary, but decrease the paralysis chance (probably to 20%). I'll also add in that casting the spell doesn't consume material components; I had intended that it doesn't, but forgot to write that in.

Thanks for the critique! (And for ignoring the strange name; I think it sounds good in context of the world, but as a generic home-brew #1458 name it just sounds weird)