This can be the result of cards that allow you to play extra lands such as Azusa, Lost But Seeking, green land ramp such as Cultivate, opponents playing fetchlands and then cracking them in the same turn, or even your own Path to Exile targeting an opponents creature when it swings at you during combat after theyve already played a land
I remember looking at vanilla creatures that weren't particularly good deals, required obscene amounts of colored mana, and had names that seemed like they'd been crafted by pulling scrabble letters out of a bag blindfolded and thinking this was one of the best things I'd ever seen

Muddle in the Middle ($7 $14) Aurelias Fury $8 Boundless Realms $8 Fiery Gambit $8 Form of the Dragon $8 Gleeful Sabotage $8 Goblin Bushwhacker $8 Yore-Tiller Nephilim $8 Triskelion $8 Sheltering Ancient $8 Pucas Mischief $8 Pull from Eternity $8 Magewrights Stone $8 Manaweft Sliver $8 Knowledge Pool $9 Archetype of Endurance $9 Leveler $10 Souls Attendant $10 Lichs Mirror $10 Lightning Storm $10 Nezumi Shortfang $10 Paradox Haze $10 Not of This World $10 Memnite $12 Norns Annex $12 Burning Inquiry $12 Balduvian Rage $12 Frozen Aether $12 Spellweaver Volute $12 Spike Feeder $13 Sundial of the Infinite $13 Funeral Charm $13 Grand Architect $13 Herald of Leshrac $13 Ravenous Trap $13 Undead Warchief $13 Misthollow Griffin $14 These 36 cards represent the lower middle class of Mystery Booster foils, and their futures will vary pretty widely

Green Goblin's last ability counts the number of cards you have discarded previously this turn, including the one you discard to Green Goblin's own ability