Unholy Strength Unholy Strength is a fairly simple spell for one black mana, it gives an enchanted creature a fairly paltry +2/+1 in stats but it's a limited staple that pops up every so often
So, my evaluation comes from my own biases, which boil down to: play the sort of cards and decks that lets everyone at the table have a chance to breathe, play Commander, and have at least a decent chance to do the thing that their deck wants to do
What Happens if you Copy a Modal Spell
Given how Steamflogger Boss, the first Contraption card, actually debuted in a black border set, that would probably be most players first guess
Plus, his enters-the-battlefield ability can hurt your ability to stop him from flipping
Its probably best in Morph decks, but still fun here