Intraguild predation (IGP) combines predation and competition. The significance of IGP-models in many natural groups is becoming increasingly clear. In these IGP-systems, we sometimes witness a notable ecological phenomenon called top-down regulation, in which predatory activity at a higher trophic level influences the community structure of lower trophic levels. This talk focuses on how the anti-predator behavior of dangerous IG-prey regulates the top-down effect in an ecosystem. To accomplish this, we developed a three-layered IGP-model incorporating the Holling type-I and type-IV functional responses for interactions of shared-prey with their predators and between IG-prey and IG-predators, respectively, along with the anti-predator behavior of IG-prey through direct killing of primarily juvenile predators. This study provides adequate requirements for all equilibria to exist and be locally stable for the proposed IGP-model. Sufficient conditions for species persistence and extinction are discussed analytically. Depending on the initial population size, the IGP-model exhibits hysteresis cycle and undergoes a catastrophic shift to extinction of the IG-predators by altering the strength of the IG-prey`s group defense. In a nutshell, our IGP-model fails to show top-down regulation in the presence of the dangerous IG-prey`s anti-predator nature, but in its absence, it does.