Monster Rancher 4

Monster Rancher 4 (PS2, 2003) is the quirkiest entry in the cult-classic monster-raising series, where you train, breed, and battle creatures generated from your own CDs/DVDs (yes, really). Its open-world exploration and revamped combat (3D arenas, combo attacks) add depth, while the “Monster Fusion” system lets you splice bizarre hybrids. Janky AI and a brutal difficulty curve test patience, but its charm and novelty—like summoning a dragon from your Britney Spears CD—are unmatched.