Common object is different from common intention as it does not require a prior concert and a common meeting of minds before the attack. It is enough if each has the same object in view and their number is five or more and that they act as an assembly to achieve that object. The common object of an assembly is to be ascertained from the acts and language of the members composing it, and from a consideration of all the surrounding circumstances. It may be gathered from the course of conduct adopted by the members of the assembly. What the common object of the unlawful assembly is at a particular stage of the incident is essentially a question of fact to be determined keeping in view the nature of the assembly, the arms carried by the members and the behavior of the members at or near the scene of the incident. It is not necessary under law that in all cases of unlawful assembly, with an unlawful common object, the same must be translated into action or be successful. Under the explanation to section 141, an assembly which was not unlawful when it was assembled, may subsequently become unlawful. It is not necessary that the intention or the purpose, which is necessary to render an assembly an unlawful one comes into existence at the outset. The time of forming an unlawful assembly is not material. An assembly which, at its commencement or even for sometime thereafter, is lawful may subsequently become unlawful. In other words it can develop during the course of incident at the spot eo instante. Ram Lal v. State of U.P., 2016 (92) ACC 399.