Olivia and Mutavault

[MementoMori]

If you use {Olivia Voldaren} to steal an animated {Mutavault}, what happens when Mutavault stops being a Vampire?

I'm thinking you'll keep it, since control- changing effects are in a higher layer than type-changing effects, but I want to make sure.

[Paraluke]

Yes you will retain control...can't really find a rule to pin this but I believe both of us are right...

RESOLVED

[Double-O-Scotch]

"For as long as you control Olivia"

[MementoMori]

Yeah, I get that. I just wasn't sure if being a Vampire mattered other than making it a valid target. Like how {Runner's Bane} falls off if the enchanted creature's power goes above 3.

After a little Gatherer searching, I found {Cytoplast Manipulator}, which works similarly to Olivia but has some more useful rulings. So yeah, Olivia's controller would keep Mutavault until Olivia left the field.

[Paraluke]

The control change lasts as long as Cytoplast Manipulator is on the battlefield. It doesn't end if the creature loses all its +1/+1 counters, it stops being a creature, or if Cytoplast Manipulator becomes untapped.

Thanks for the tip, just pasted what  {Cytoplast Manipulator} says.