When dealing with Retinazer, get as close to him as you can and hit him with a flail, like the Dao of Pow (the weapon mentioned earlier). With Spazmatism, his...
You'll have to destroy Skeletron Prime to get the Souls of Fright, get the Arms Dealer for the Illegal Gun Parts and mine for Iron / Lead Ore for their...
You may have pushed her too hard or rushed things and confused her as a result. You may need to start fresh, putting the halter on at first for only...
Villagers will sometime trade for string. Witches have a chance to drop string upon death. Steal string from other players. Use Creative Mode/Commands.