Duelingbook Forum

I have a plant monster and an open Rivalry.
My opp has two dragons on field.
Can i take control of a dragon from my opp ? cause sheet says it becomes plant.

ty guys

Given that you can't perform a Summon of a different type/attribute/whatever depending on the floodgate even the board state before and after the Summon fulfill the floodgate's condition, I wouldn't be surprised if you can't.

You can take control of an opponent’s monster that’s the wrong Type/Attribute with a card like
“Mind Control”. If you do, it’s sent to the Graveyard immediately after you gain control of it.

King_Kai is correct. And since Rikka Sheet uses the "and if you do" conjuction, which considers both parts of the effect to happen simultaniously, you should keep that opponent's monster on field, at least until the effect of Rikka Sheet wears off during the End Phase.