That first legendary, an Unfriendly Giant launcher (with tracking!) from a loot cave engram. It was my pride and joy and I levelled it up immediately. Of course, loot cavers will remember that to keep space on your character for engrams, you had to constantly delete weapons and armour. Sometimes you did this in a hurry so you could keep vacuuming up more engrams. Sometimes you deleted legendaries that you wanted to keep... :(