Prior studies indicated that Hells Bells-like underwater speleothems might occur in the sinkhole (cenote) Xkolac in Yucatán, Mexico (Ritter S.M, 2020). In order to verify, the cenote was explored in February 2020 by a team of five divers and four scientists. Below ~52 m water depth, the limestone walls actually revealed brownish calcitic coatings forming pine-cone like structures at overhangs. These novel underwater speleothems were termed as "Piñas de Yucatán". Based on this discovery, Hells Bells and Piñas de Yucatán might represent a novel sub-type of underwater speleothems, the redoxithems, which are formed due to microbially promoted calcite precipitation in pelagic redoxclines.