Do I put the card on top of my deck before flipping battle cards?
[Source: WotC]
Yes. The card you put on top of your deck (if any) will be the first battle card you flip.
So I’m attacking with Dinobot Snarl - Desert Warrior with 8 damage counters on him, he’s attacking
Volcanicus, who has
Electrified Spikes on him. Snarl flipped enough damage to KO Volcanicus, but for Volcanicus’ defense flip, he hit the two orange pips to activate Electrified Spikes. Which would do the KO damage on Snarl. So how is damage assigned? And whose damage goes first? Or is this a double KO?
[Source: WotC]
Electrified Spikes’ ability happens before attack damage, so in this scenario,
Volcanicus would save himself with Electrified Spikes and KO Dinobot Snarl - Desert Warrior.
Alternatively, you could try telling Volcanicus to stop hitting himself.