Probe

You will never find one wandering. Each probe peels off a lit segment of The Destroyer when that segment takes a hit, so they are a byproduct of your own damage and nothing else spawns them. Their lasers leave from slightly above where the sprite suggests, which is enough to make lazy dodging fail.

Every one you kill leaves a heart, and during a long worm fight those hearts are often the only healing you get between potion cooldowns. A few are genuinely useful. Letting the count climb is what kills people, since a dozen firing from different angles out-damages the boss itself.

• Fast or piercing weapons clear them without aiming. Slow melee swings whiff on something this small and this quick.
• Walls do not help, since they travel through everything. Boots or a gravitation potion let you leave a laser line instead.
• Against Mechdusa in a Zenith world they appear at half the usual rate, so plan for much less free healing.
• The Golden Shower is a poor pick here on higher difficulties, since it deals reduced damage to the worm and its probes.