It's possible I'm slightly overvaluing the power level of this card
Having transform/DFCs return was the best way to represent the final bosses (when was the last time FF had a single phase final boss?) and characters who changed
Combined with all the Bloodletter of Aclazotz combos, this gives Mono-Black Midrange a good chance to end the game on the spot
Like so many other recurring mechanics without an official name, this has been named after the first card where it appeared, Act on Impulse
Drakuseth, Maw of Flames feels right for the deck and Elesh Norn, Grand Cenobite can help clear out pesky small creatures (and help avoid some of the combos based around them from popping up)
Source: MTGStocks Crashing Footfalls is also pretty scarce, given it was never reprinted outside Mystery Booster 2 and Special Guests (Violent Outburst has been reprinted in Foundations: Jumpstart )