High point of view. The giraffe has advantage on Wisdom (Perception) checks that rely on sight. 
Tall build. The giraffe has disadvantage on Strength saving throws against getting prone and standing up cost 3/4 of its movement.
Charge. If the giraffe moves at least 20 feet straight toward a creature and then hits it with a head slam attack on the same turn, that target takes extra 2d6 piercing damage and increase the DC for the save by 2 . If the target is prone, the giraffe can make one hooves attack against it as a bonus action.

Multiattack. The giraffe makes two hooves attacks.
Head slam. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 18 (4d6 + 4) bludgeoning damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.
Hooves. Melee Weapon Attack: +6 to hit, reach 5 ft., one Large or smaller target. Hit: 8 (2d6 + 4) bludgeoning damage.