Your beast savages an enemy. making that creature its prey. When it grows bored, the beast launches itself at a new foe, drawing that creature's attention.
Your beast companion gains 10 temporary hit points, and your beast companion marks the target until the end of the encounter or until your beast companion attacks a creature other than the target. Until the end of the encounter, whenever your beast companion makes an attack roll against any creature, it marks that creature until the end of the encounter or until it makes an attack roll against a different creature.