Dugee
Dugee was a Mycon purity monitor, which apparently involved choosing which buds are allowed to flourish, and which must be exterminated, effectively meaning he was in control of the Mycon's evolution to some extent. He claims to have died of "general misfunction" 57,283 years ago. Somehow speaking through a living Mycon Podship captain during a conversation (or what passes for conversation with the Mycon) with The Captain, Dugee suddenly intruded to quickly state his occupation, as well as both the time and cause of his death. After doing so, he receded back to wherever it was he came from, leaving the original Mycon back in control of its speech. The reason for his sudden appearance and subsequent disappearance remain utterly obscure to all but the Mycon themselves.
Curiously, Dugee's life actually predates the height of the Sentient Milieu by some 32,000 years. In fact, his claims to his age would make him the closest known sentient being to the disappearance of the Precursors, putting him before even the (currently living) Slylandro Speaker Content to Hover, who is apparently over 20,000 years old. However, his transient state and typical obscure Mycon disposition would make getting any information from him on this time period nigh-impossible.