S05E144: The Arcobaleno Seals

Colonnello continues to overwhelm the two. He is defeated when Gokudera distracts Colonnello for Tsuna to use X-burner on him. Colonnello gives Tsuna the Arcobaleno Seal, which causes all the Vongola rings to glow simultaneously. Skull makes his appearance and is revealed to be scheming something with Viper. Later, a person pretending to be Tsuna provokes Kyoya Hibari and Mukuro, causing them to pursue the imposter. Tsuna and Reborn are heading to Chrome's hideout to give her some bentō and end up meeting Mukuro and Hibari. Mukuro and Hibari begin their battle against each other.