Exchange rate: approximately 159/USD
Once you pay Dismembers Phyrexian mana costs with 4 life, on the end step, youll trigger Yshtolas draw effect
With Day of Black Sun, you can destroy cheap, aggressive creatures at a reasonable cost while leaving your larger threats untouched
Double Strike also acts like First Strike, granting both a First Strike attack and then a second attack when regular combat damage is resolved
Beware the merrows, whose envy and covetousness surpasses even that of the ravenous whirlpools where they dwell. The Book of Other Folk Illustrated by Mike Dringenberg Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Legal Brawl Not Legal Legacy Legal Comp
You have to get rid of a second card to pay the cost, but the tempo gain and protection offered in that exchange are much greater than the loss suffered by pitching some other blue or green card