Frenzied Saddlebrute

Read the second line closely before you count it as a personal payoff, because it does not say "your creatures." It says all creatures, and it points them at your opponents and the planeswalkers your opponents control. In a duel that scope collapses to nothing: your team already wants to hit the only opponent there is, and the summoning-sickness lift on freshly cast creatures is the whole return. Add players to the pod and the effect turns inside-out: every creature anyone controls, opponents included, can swing at your opponents without waiting out sickness, so you are handing everyone a shared attack enabler and betting the extra combat lands on the players across from you rather than on your own board. The grant is also narrower than the words first suggest. It removes the sickness restriction only for attacking your opponents and their planeswalkers; it does nothing for tapping toward activated abilities, and blocking never cared about summoning sickness, so it adds nothing on defense. It is a combat-direction lever, not a general cure for new creatures. Being a 5/4 with haste, the body carries the aggression on its own, and any creature you cast the same turn it comes down gets to attack immediately. Board-wide haste has usually lived on enchantments like Fervor and Fires of Yavimaya; welding it to a creature means the anthem shows up as a threat rather than a static permanent waiting on the next thing you play.