The mine

 The recently changed mine now has 'puffle rescue' . Look for the black puffle in puffle rescue and follow the shadow but watch out for :)...  There is a tunnel going into a mine for coins. To your PENGUINS left are two hard hats and a yellow hammer thing. Walk up to them and click 'yes' I would like to pick them up.  then dress ONLY with your new hard hat and dance to dig. On the mud patch dig up coins. If there are no coins where you are digging, dig somewhere else. If you go through past the mining area you will arrive at the hidden lake. There is a door partly submerged in the lake click on the note and De ja vu it is what I told you. If you follow the shadow Blah Blah Blah You will get a key to the door!