The devastating set of huge earthquakes that struck Japan last week is having an unexplained side effect: copious amounts of a mysterious foam-like substance is covering the streets. According to FOX News: Twitter users began posting photos of the unexplained foam shortly after the tremors receded. 地震で地下から泡は出るわ(福岡天神) ラウンドワン上のピンは落ちてくるわ コンビニの中はグッチャグチャになるわ 大変やな……地震ってあんまり経験してないから気おつけとこ、皆さんもお気をつけて pic.twitter.com/5lQNuyK0Sd — ロキア (@R0KlA) April 15, 2016 Some have speculated that an underground pipe had burst, although the origin is still unclear. 天神が謎の泡、、？ pic.twitter.com/H4YP8KFcWp — TAKAFUMI (@The_takafumi) April 15, 2016 福岡の天神どうしたん 泡だらけやん pic.twitter.com/JE2QKxayBT — はるぴよ⑅⃝ (@_xPIYOx_) April 15, 2016 A city spokesperson told The Independent they did not know anything about the bubbles. What exactly the bubbles are made of is still a mystery. One Twitter user called it “disgusting.” Check out a video of the mystery foam below: