this.color.setWhite(true);
this.power = new MageInt(3);
this.toughness = new MageInt(3);
// {3}{G}{W}: Monstrosity 1.
this.addAbility(new MonstrosityAbility("{3}{G}{W}", 1));
// As long as Fleecemane Lion is monstrous, it has hexproof and indestructible.
Effect effect = new ConditionalContinousEffect(
new GainAbilitySourceEffect(HexproofAbility.getInstance(), Duration.WhileOnBattlefield),
MonstrousCondition.getInstance(),
"As long as {this} is monstrous, it has hexproof");