Multiattack. The manticore makes three attacks, using Rend or Tail Spike in any combination.
Rend. Melee Attack Roll: +5, reach 5 ft. Hit: 7 (1d8 + 3) Slashing damage.
Tail Spike. Ranged Attack Roll: +5, range 100/200 ft. Hit: 7 (1d8 + 3) Piercing damage.