Playmats measure 13.5" x 23.75"
If you win the flip, prevent all combat damage that would be dealt by that creature this turn
You can also make use of fight effects, but those tend to be far riskier since the opposing creature will also damage yours
The archetype that Sliver Swarm focuses on entirely is Combat: the deck provides tons of cards that greatly increase its effectiveness in combat, from dishing out extra damage with Bonescythe Sliver to providing evasion with Cloudshredder Sliver to drawing card on combat with Synapse Sliver
all Cap is doing is tapping the signpost, telling you to fill his deck with heroes and letting them get to work
As long as neither player is manipulating their library or using their graveyard, using a Millstone does nothing but reveal information until the player being milled runs out of cards, but it took more explanation than you can possibly imagine to make players understand this