PowerplayingPowerplaying is not when you auto-kill something. The murder of something or someone is a godly action, thus it is more godmodding. Powerplaying is when you control, purposefully or accidentally, something that is not of your creation and define it's attributes. Powerplaying would be my controlling some aspect of the universe, it's qualities, and it's reactions without being the GM or someone with the right or authority to do such. In this case, picking up the doll without knowledge of it's characteristics and making it be bitten. There's no time for reaction, nor would you have the necessary information, obviously, to state that the action would go through flawlessly. You forced, by your own hand, the entire scenario. For example:
Jon threw a boomerang at Rex
The boomerang missed by flying out the window. Rex threw a fireball at Jon
Jon dodged the fireball by rolling under at able. Jon threw threw the table at Rex
The table fell apart before reaching Rex and the ceiling fell on top of Jon from above. Rex ran forward throwing super fast knives at Jon
Jon dodged the rubble falling from the ceiling but was stabbed by one of the knives.
A desk behind Jon fell on him, pinning him down, then Rex moved in and punched straight at Jon's face
Jon died.
Jon's body exploded randomly into flames
Powerplaying is also when, like what Bunny thought, when my statements or the actions of my characters cause an unwarranted or unallowed movement or action or decisions of another character that is not mine. That is forceful controlling of another character, though not necessarily in a godly fashion. So, for example:
Rex ran at Jon and threw a super fast knife at Jon
Jon dodged the super fast knives and pulled out a gun
Superfast knives cut Jon's jacket. Rex threw another one and it stabbed into Jon
Jon was stabbed and quickly pulled out the knife from his leg
When Jon pulled out the knife his finger's slipped and the knife fell down and stabbed him in the foot
Jon pulled the knife out his foot and threw a fireball at Rex
Jon missed Rex because he is tired from blood loss. Rex threw a fast knife at Jon.
Jon dodged and hid behind a wall outside
Rex found Jon just as the wall crumbled on top of Rex. Rex grabbed Jon and broke his neck
Those are examples of powerplaying.
If you don't have enough information, you can't just make something happen just because. It's all to easy to ask someone "what would happen if...?" Another thing is you can't control the enviroment just because. You also cannot say how another character will react or take damage. You can't instantly inflict damage on them, automatically grab them, or automatically negate, cancel, or thwart their attacks.
What makes powerplaying is when there is no "in between". There's no "Rex tried to-" or "Rex attempted too" or "Because Jon did this, it allowed Rex to-". There's no valid explianation or a pause that would allow a fellow Rper the ability to react to the situation. For example, what I did. I sent a punch straight for the character's chest because he put himself within range, however, I still implied that the punch was sent at him, never that it would unavoidably land.