Pair of Kings (2010)

S3E17 Loathe Potion No. 9

Boomer worries that Mikayla's growing bond with Boz might turn into a romantic interest, and he can't bear the thought of losing another brother to her distractions. To prevent this, he concocts a Dirt Fairy potion meant to make them repel each other. However, the potion backfires spectacularly, escalating their relationship into an all-out brawl instead.