Viserion and Rhaegal Accepted Tyrion
When Tyrion entered the dungeon where the two dragons were being held, the scene was incredibly tense. We know that no one is safe in George R. R. Martin's realm, so fans truly weren't sure if Tyrion would survive or if he would be burned to a crisp. At one point, one of the dragons threatened him by beginning to blow out a flame, but then he stopped. He recognized Tyrion as a friend. He let Tyrion touch him and remove his chains. The other dragon then simply presented his neck to Tyrion to have his chain removed. They recognized some kind of kinship in Tyrion, some kind of connection that is typically only seen with Daenerys. In fact, when Daenerys visited them in season five, they didn't react so kindly to her. (HBO)