It looks like an I, Medusa with bright cyan skin and a yellow tail. Instead of snakes, Bolt-dusa has lightning bolts for her hair with eyes on each bolt.
When Found (assuming default)
Second Mii: So you're telling me a weird colorful fog surrounded my head and took control of me? Wow, that's scary!
Lead Mii: Don't worry, we took it down pretty easily.
Third Mii: Yeah. But never mind that, does anyone else's... Everything feel weird, numb and tingly?
Second Mii: It's not another weird fog is it?
Fourth Mii: Hopefully not... Speaking of which, does it suddenly feel super hot in here or is it just me?
Lead Mii: ...
Second Mii: Oh no, when one of us goes silent, it's a bad sign.
Offscreen Voice: SCREE!
Offscreen Voice 2: Sksksksksk...
(If the second Mii was not the one taken over, this scene is skipped.)
When Found (If second Mii was not the one taken over)
Head Fog: Ỷ̏̽͏͖̹̘͚͕̗O̡͕͇̺͍̤̤̲̜͆̍͌ͪU̢̝ͤͫ̅ͫ̈́͛͐͆͝.̮͓̲͕͔̣͎͒ͬ.̵̛̬̹̉ͦ̑.̦̲̮̖̰̆̽̑̌͌͟ H̷̭̳̋ͮͣ̏͘A̢̼̣̳͓ͩͪͦ̂̌̀V̤̺̲̳ͬ̆̔̏̾̋ͣ͘E͐̍̅̊͌̽͛ͮ̄͏̼̝͍͙͖͡ B̧̛͈͉̻͍͔̺̟̋ͣ̆͗̅̅̉Ẽ̼̰͍̹̬͉͔̦̍͐ͯͥ̅̃͠Ë̺̗̼̱̜̦̝̘́͒ͩ̏͐͑͘͟͠N̈͋̾̍͊̏̕҉̱̤̫͇̰̮̗̤͈̫̝̯̳̯̮͒͊͘͡ S̜̻͂̑ͭ͑͌͌͆ͦ̚͡P̴̮̗͕͓̊͋̂̑̄́ͩ̌̕͘A̠̙̪̥̾ͮ͂̈́̂͛͌ͅR̤̝̙̭̝̮̿ͮ̄ͫ̀ͩ͟͞E̵͂ͧͥ҉̹D̥̫̬̙̖̑̍ͪ́̅̒ͨͤͅ!̴̛̼͎̩̱̙̼̥̰͋ͦ͋̑̈̐ͯ̚!ͤͤ҉̞͇̗͞!̧̣͈ͣͤ̂
Lead Mii: Um... What was that?
Possesed Mii: What? I Mea--
Lead Mii: Don't worry. It's fine.
Another Mii: Let's just forget about that. So, Anyway, Does anyone else's... Everything feel weird, numb and tingly?
(The Rest of the Cutscene plays out as Normal.)
A multitude of lightning bolts do huge damage to all Miis.
Electric currents create a pretty light show that may get Miis dancing.
Charges for three turns, and then brings all Miis down to one HP.
Deals massive damage to a Mii in exchange for recoil.
Can make it so that a beneficial ability can be used again. (I.e, this is so that Flare Griffin can use Phoenix Ashes over and over again)
One More Time!
Allows another action.
Lead Mii: Phew, that's a relief.
Second Mii: And best of all, my body feels comfortable again!
Fourth Mii: I don't have to poof my clothes to stay cool!
Third Mii: It feels like a lot of mental taxing has been taking place lately. It's refreshing to have just physical taxing.