function Behaviour(life, easing) {
      /**
       * The behaviour's life
       * @type {number}
       */
      this.life = Util.initValue(life, Infinity);

      /**
       * The behaviour's easing function
       * @type {function}
       */
      this.easing = ease.getEasing(easing);

      /**
       * The behaviour's current age
       * @type {number}
       */
      this.age = 0;

      /**
       * The behaviour's current energy
       * @type {number}
       */
      this.energy = 1;

      /**
       * Whether the behaviour is dead
       * @type {boolean}
       */
      this.dead = false;

      /**
       * The behaviour's parent emitters
       * @type {Array}
       */
      this.parents = [];

      /**
       * The behaviour's unique id
       * @type {string}
       */
      this.id = "Behaviour_" + Behaviour.id++;

      /**
       * The behaviour's name
       * @type {string}
       */
      this.name = "Behaviour";
    }
Create a new Behaviour instance
@param {number} [life=Infinity] - The behaviour's life
@param {string} [easing='easeLinear'] - The behaviour's decaying trend, for example ease.easeOutQuart