The swarm appears as a purple mist that surround the hive. When Samus gets too close the swarm will follow her until she can submerge herself in water. While the swarm deals high amounts of damage, Lightning Armor can mitigate most of it.
Curiously, after Samus acquires the Gravity Suit, all previously encountered Fleech Swarm hives are inactive and dried up.
- Inhabitants & Eco System of SR388 (p. 18)
- FLEECH SWARM
- "These hives of purple mist-like insects promise to inject much stress into your life. Seeing one is an indication that the next few moments are going to be a mad dash to the nearest water supply. Should you walk near a Fleech Swarm hive, the mist swarms you and persistently deals damage until you take a dip and wash it off. The Lightning Armor is a huge help in mitigating the damage, but without it, expect heaping helpings of pain."
- Walkthrough (p. 62)
- FLEECH SWARM
- "You don't run into Fleech Swarms very often, but when you do, move fast. The Fleech Swarm's mist latches on to your Power Suit and rapidly drains your health. The only way to dislodge it is by jumping into a pool of water. Thankfully there's always a pool not too far from a Fleech Swarm's location.
Whenever you see a Fleech Swarm, throw on your Lightning Armor and move quickly. The sooner you find water, the better."
- The Fleech Swarm is one of the two enemy types in Samus Returns that were not present in Metroid II: Return of Samus, the other being the Paraby.
- They are similar to the Ingstorm from Metroid Prime 2: Echoes.