Hey there, every time i get back into the game ,i glitch through the floor and today i've found this , can someone plz explain it to me what it is ? some future content or an easter egg ? (under cave)

interesting. That kinda looks like the figure that appears momentarily in the middle of the woods between house and mine, I'm guess since there's a bit of a path that at some point the mine is intended on being extended (That's a given) and that somewhere beneath the middle of the woods there, is this dudes tomb... What that might entail beyond that.. I dunno... I'm guess That place has been drawn up since the figure started appearing, which was at least the earlier version, but possibly earlier.