Zerg Regeneration. The Zerg Roach regains 10 hit points at the start of its turn as long as another Zerg is within 50 ft. if the Roach takes psychic damage, this trait doesn't function at the start of it's turn. The roach only dies if it starts it turn with 0 hit points and doesn't regenerate.

Hardened Carapace. If the Zerg Roach takes the dodge action, it gains +2 to it's AC and all of it's saves.

Multiattack. The Roach makes two talon attacks.

Talon. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) [piercing type] damage. 

Bile Spit. Ranged Weapon Attack: +4 to hit, range 20/40 ft., one target. Hit: 6 (1d8 + 2) [bludgeoning type] damage.

Parry. The Roach adds 4 to its AC against one melee attack that would hit it. To do so, the Roach must see the attacker.

Legendary Resistance (1/Day). If the Roach fails a saving throw, it can choose to succeed instead.