Inside the Tentacle Cave manga volume 1 features story by 
Umetane and art by Abi. 

Deep in the tunnels of an abandoned mine lurks a demon that absorbs the power of anything it touches: the Black Ooze. When it consumes its first human male, it acquires both intelligence and ravenous sexual desire, much to the distress of a sorceress who mistakenly enters its domain. The heroes who seek glory and riches in these caverns are about to learn why monsters should be feared!