So on MTGO, I've created a casual deck with Golden Guardian. The plan is to activate Guardian's ability to fight my own Syndicate Trafficker, then activating Syndicate's ability to sac the Golden Guardian in response, to keep Syndicate alive and transform the Guardian. But it doesn't work. They fight and the Syndicate dies immediately without any option/stack. Is this a bug, or does the fight happen without going on the stack?
They don't fight in your scenario and Trafficker should not have any damage marked on it. You put the ability from Golden Guardian on the stack. Before that resolves, you sacrifice it to Trafficker. Then the ability resolves and does nothing since the Guardian is no longer around to Fight.
The Guardian will only transform if it dies *after* its ability resolves. Since it died before the ability resolved, nothing happened. You will be unable to do what you want with just these two cards. You need to let the Fight happen which means both the Guardian and the target need to be on the battlefield when the ability resolves.
EDIT: I may have misread. It actually sounds like you are letting the ability of the Guardian resolve. As mentioned above, you can't do what you want as the Fight is part of the ability. It uses the stack in that the entire ability is on the stack for you to respond to but the Fight doesn't happen until the ability resolves (which is how basically everything works).
They fight and the Syndicate dies immediately without any option/stack. Is this a bug, or does the fight happen without going on the stack?
You should be able to respond to Guardian's ability (but your combo still won't work, as WizardMN stated).
There probably is some setting you need to adjust.
The Guardian will only transform if it dies *after* its ability resolves. Since it died before the ability resolved, nothing happened. You will be unable to do what you want with just these two cards. You need to let the Fight happen which means both the Guardian and the target need to be on the battlefield when the ability resolves.
EDIT: I may have misread. It actually sounds like you are letting the ability of the Guardian resolve. As mentioned above, you can't do what you want as the Fight is part of the ability. It uses the stack in that the entire ability is on the stack for you to respond to but the Fight doesn't happen until the ability resolves (which is how basically everything works).
There probably is some setting you need to adjust.
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