Multiattack. The myrmidon makes three Trident attacks.
Trident. Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:7 (1d6 + 4) force damage, or 8 (1d8 + 4) force damage if used with two hands to make a melee attack.
Freezing Strikes (Recharge). The myrmidon uses Multiattack. Each attack that hits deals an extra 5 (1d10) cold damage. A target that is hit by one or more of these attacks has its speed reduced by 10 feet until the end of the myrmidon's next turn.
Elemental myrmidons are Elementals conjured and bound by magic into ritually created suits of plate armor. In this form, they possess no recollection of their former existence as free Elementals. They exist only to follow the commands of their creators.