Multiattack. The Spear tower makes three attacks, choosing any combination of Pike, Hammer and Crossbow.
Pike. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: (1d10+4) Piercing damage.
Hammer. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: (1d4+4) Bludgeoning damage. If the target is a creature, it must succeed on a DC 16 Strength saving throw or be pushed 5 feet away and knocked prone.
Crossbow. Ranged Weapon Attack: +3 to hit, reach 100/400 ft., one target. Hit: (1d10+1) Piercing damage.