Yes, Frenzy, but not only !
The Beast is also what keeps the Kindred from being brainless zombies. Without a Beast, the Kindred have no emotions, no drive, no survival instincts, and no willpower.
As the Kindred is stressed out, by hunger, by fear, by threats, by attacking ennemies, by blood.. The Beast tries to take over and act out of survival.
The Beast taking over because of Hunger, the presence of Blood, threarts... it's called Frenzy. The Beast will take over and attack and/or feed over anything in sight. The Vampire weapon against Frenzy is Self Control.
When it's because of fear ; threats, fire, sunrise, attacks.. It's called rotschreck (the fear of red !). The Beast will take over to flee whatever caused the rotschreck, pushing everything on the way to "as far away as possible". The Vampire weapon against Rotschreck is Courage ^^