Gerridae

Bred to the Saddle. The gerridae can't be charmed or frightened while it has a rider.

Water Bound. For every hour the gerridae spends on dry land, its hp maximum is reduced by 2 (1d4).

Water Walker. The gerridae can move across the surface of water as if it were harmless, solid ground. This trait works like the water walk spell.

Multiattack. The gerridae makes one Bite attack and one Claw attack.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) slashing damage.