Probe

The Probe is an enemy which spawns from one of The Destroyer's red lit segments. It fires lasers both from inside the Destroyer and detached from its master. It can pass through blocks.

Probes will only detach from The Destroyer after it has taken a fair amount of damage.

Probes make fighting The Destroyer a much easier task as the hearts they drop will keep you alive.

Tips
Probes are fairly small, fast, flying enemies who can deal consistent damage in a moderate amount of time. As such, most melee weapons are not recommended. Some good ways to defeat them are to use some ranged weapons such as a repeater or Minishark. Any fast firing weapon such as the Crystal Storm will do. These types of weapons allow you to kill the Probes as well as being able to deal damage to The Destroyer. It helps to use a Gravitation Potion or Rocket Boots/Spectre Boots/Frostspark Boots. These allow easy movement to dodge the Probes as they come towards you and to dodge the lasers.