You control at least four other creatures with +1/+1 counters on them.
Mana Needed
({2} magic symbol) ({B} magic symbol) available.
Steps
On the end step prior to your turn, cast
Saw in Half by paying ({2} magic symbol) ({B} magic symbol) , destroying
Slurrk and creating two token copies of it with base power equal to half the destroyed creature's power and base toughness equal to half the destroyed creature's toughness, rounding up each time.
Put one
Slurrk token into your graveyard due to the legend rule.
Each
Slurrk triggers once, and
Simic Ascendancy's first ability triggers twice.
Resolve both
Simic Ascendancy triggers, putting ten growth counters on it.
Resolve the first
Slurrk trigger, putting a +1/+1 counter on each creature you control that has a +1/+1 counter on it.
Simic Ascendacy's first ability triggers for each counter placed this way, putting that many growth counters on it.
Repeat from step 5 for the remaining trigger.
At the beginning of your upkeep,
Simic Ascendancy's second ability triggers, causing you to win the game.