Thanks guys! I had a baby aiptasia in the tank recently so I used some aiptasia x to kill it. Glad to hear these are not aiptasia spawn and are harmless lol
Pineapple is short lived and often in shaded areas. harmless to the tank. Pineapple sponges fade over time because they are a sponge that has a silicate skeleton. The mystery appearance in an established tank often is an indication of silicates in the rodi. They usually prefer darker places( why they end up in sumps). They will occasionially be on top of rocks or on the old stony growth at the bases of a coral skeleton. They can grow on the glass as well. Pineapple sponges usually don't last long in brighter areas. More often than not, they start to turn green or brown from algae or diatoms growing on them and eventually smothering them out.