I’ve had this spell in mind for years, perhaps decades, and never written it up. An NPC wizard of mine in a 1990s Ars Magica game used to transform himself and also animate statues, but I’d never written it properly. In simple terms the person is transformed into a living statue, or as I like to think into an almost unstoppable juggernaut.
An animated status is almost unbeatable by mundane means. Normal weapons are not designed to damage creatures like this, and likewise defending against one would be a terrible challenge.
Given the effect that transformation has on targets with magic resistance this is a very defensive form, and not without some drawbacks. The target will find themselves weighing far more than most structures can tolerate, and looking totally unnatural.
Form of the Iron Juggernaut
Muto Corpus / Terram 45, R: Personal, D: Diameter, T: Ind
The caster’s body is transformed into solid metal, which can move as normal. A metal pin is applied during casting, and removed by the caster to end the effect prematurely if they wish.
Casting requisites are required for carried equipment, although clothing and personal effects are also transformed.
(base 25 for solid inanimate object, +1 D: Diameter, +1 to allow movement sub-effect, +2 for metal)
It is certainly possible to make the effect a little lower to only transform to stone (-5 levels), or allow a longer duration as Sun (+5 levels), but this is what I have in mind or a current character.