Wish Upon A Star

[PvK]

How about if you could wish for any unit (if one is in the world somewhere you get a random one from the world itself) but there is a MR contest to see if it shows up subservient or hostile, and maybe a random chance whether a hostile unit shows up to attack your province, or as an assassination-type encounter?

For thematic/variety purposes, there could be positive modifiers if the summoned unit is the same type as the caster (i.e. demon/undead/size, and/or blood/death/nature/water/air give bonuses to demons/undead/animals/aquatics/fliers respectively) and some modifiers for other types (mindless are easier, horrors are hard or impossible, maybe a minus for size...). Ok, I like detailed and uncertain mechanics.