Wyvern but op and big it also has a boat

Boat. It throws an infinite amount of boats at you does not count as a turn. It takes its time to build a boat from the surroundings to then through it at you it is invincible during this action. This can only after every player has made their turn, once this attack is played the monsters next attack does half as much damage.

Ice burg. This attack makes a ice burg appear in front of all moving people making them run into it, they are unable to attack but able to move and or flee from the battle, bonus action 

Multiattack. The wyvern makes two attacks: one with its bite and one with its stinger. While flying, it can use its claws in place of one other attack.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one creature. Hit: 11 (2d6 + 4) piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.

Stinger. Melee Weapon Attack: +19 to hit, reach 100 ft., one creature. Hit: 111 (999d6 + 2) piercing damage. The target must make a DC 20 Constitution saving throw, taking 29 (100d4) poison damage on a failed save.

Throws a boat at you.

Ice burg appear in front of player.

Boat. It throws a boat at you

BOAT!. It throws a boat at you but it hits every time and causes a 3d100 attack on enemy only used once every 2 turns

BOAT. Big boat thrown at you never misses deals 1d20 with bludgeoning of knocking you backward until you hit something (this means if you are on a cliff next to endless ocean to go in the direction it hit you till you hit something, you also hit that object with twice as much power as the monster hit you and it deals 2d20.)