it can easily become a +10/+10 boost for one mana
If it's a nonland card, you may cast it by paying rather than paying its mana cost

Synthoids Aang and La, Ocean's Fury Aang's Iceberg Aang's Journey Aang, Destined Savior Aang, Master of Elements Aang, Swift Savior Aang, at the Crossroads Aang, the Last Airbender Aatchik, Emerald Radian Abandon Attachments Abandoned Air Temple Abandoned Campground Aberrant Manawurm Abhorrent Oculus Abigale, Eloquent First-Year Abigale, Poet Laureate Abomination, Terrifying Titan Abrade Abraded Bluffs Absolute Virtue Absolving Lammasu Absorbing Man Abstract Paintmage Abuelo, Ancestral Echo Abyssal Gorestalker Abyssal Harvester Abzan Devotee Abzan Monument Accumulate Wisdom Aclazotz, Deepest Betrayal Acolyte of Aclazotz Acrobatic Cheerleader Acrobatic Leap Action News Crew Adagia, Windswept Bastion Adamant Will Adaptive Automaton Adaptive Gemguard Additive Evolution Adelbert Steiner Ademi of the Silkchutes Adept Watershaper Adorned Crocodile Adrenaline Jockey Adventurer's Airship Adventurer's Inn Adventuring Gear Adventurous Eater Aegis Sculptor Aegis Turtle Aerial Doombot Aerith Gainsborough Aerith Rescue Mission Aether Syphon Aetherize Aetherjacket Aettir and Priwen Affectionate Indrik Afterburner Expert Aftermath Analyst Agate Assault Agate-Blade Assassin Agatha of the Vile Cauldron Agatha's Champion

Occasionally though, when you can convince two of your three opponents that its in their best interest, it instead serves as a four-mana Time Walk
It could create a backbreaking combo which won the game within two to three turns
Yoshitaka Amano illustrated this Double-faced Kefka, Court Mage/Kefka, Ruler of Ruin and Terra, Magical Adept/Esper Terra