Probe

The Probe is a Hardmode enemy which spawns from one of The Destroyer's red lit segments after it has taken a fair amount of damage. It fires lasers both from inside the Destroyer and detached from it. It can pass through blocks, but its lasers cannot.

Probes make fighting The Destroyer a much easier and harder task at the same time – the Hearts they drop will keep the player alive, but they are a major source of damage during the boss fight.

Tips

 * Probes are fairly small, fast, flying enemies who can deal consistent damage in a moderate amount of time. As such, most ranged weapons are superior to melee weapons in general. Any fast firing weapon such as the Crystal Storm will prove effective as well.
 * It helps to use a Gravitation Potion or Rocket Boots or one of its upgrades. These allow easy movement to dodge the Probes as they come towards the player and to dodge the lasers.