Midas Touch is an elixir you can either make or buy from the elixir consignment store if it's available - it gives your sim an interaction with certain objects (there's a thread floating around here about which ones) for 6 sim hours where all objects touched will be worth roughly twice what they normally are. I believe you can also temporarily turn sims into gold but I haven't done that yet seeing as I'm a softy.
No one can die from using the elixir. For maximum profit, I suggest getting as many Ambiguity Itself statues (the one with the hole in it towards the end of the decor-->statues section) as you can afford as well as transform in 6 sim hours (it's a rather short interaction).
I believe the Golden Touch is from the Philosopher's Stone which I haven't played with yet - I do know that's the one where if it backfires while you're trying to turn something to gold, your sim could die. I personally wouldn't try it without a deathflower or a sim with the unlucky trait, unless it were a casual game and the sim has lived a very, very, very long life.
