Amphibious: The beast can breathe both air and water.
Beast Bond: You can add your proficiency bonus to any ability check or saving throw that the beast makes.
Binding Strike. Melee Weapon Attack: STR mod. + PB to hit, reach 5 ft., one target. Hit: 1d6 + 2 + PB piercing or bludgeoning damage (your choice), and the target is grappled (escape DC equals 8 + STR mod. + PB). Until this grapple ends, the beast can't use this attack on another target.