Scute Mob’s ability has an “intervening ‘if’ clause.” That means (1) the ability won’t trigger at all unless you control five or more lands as your upkeep starts, and (2) the ability will do nothing if you control fewer than five lands by the time it resolves.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.