// At the beginning of your upkeep, you may put a 1/1 green Squirrel creature token onto the battlefield.
this.addAbility(new BeginningOfUpkeepTriggeredAbility(Zone.BATTLEFIELD, new CreateTokenEffect(new SquirrelToken()), TargetController.YOU, true));
// Threshold - Squirrel creatures get +2/+2 as long as seven or more cards are in your graveyard.
this.addAbility(new SimpleStaticAbility(Zone.BATTLEFIELD,
new ConditionalContinousEffect(new BoostAllEffect(2, 2, Duration.WhileOnBattlefield, filter, false),
new CardsInControllerGraveCondition(7),
"<i>Threshold</i> - Squirrel creatures get +2/+2 as long as seven or more cards are in your graveyard")));
}