Wikipedia
Fonticula
Fonticula is a cellular slime mold which forms a fruiting body in a volcano shape. As long ago as 1979 it has been known to not have a close relationship with either the Dictyosteliida or the Acrasidae, the two well-established groups of cellular slime molds. A 2009 paper finds it to be related to Nuclearia, which in turn is related to fungi.
Fonticula, Nuclearia, and Fungi have been united into the Nucletmycea, which is sister to the Holozoa.