Same thing happens when you get killed by Asgore and do Act > Talk.
1-4 times: "You tell ASGORE that he's killed you <once, twice, etc> before. He nods sadly."
5-9 times: "You tell ASGORE that he's killed you <five, six, etc> times. He nods grievously."
10+ times: "You tell ASGORE that he's killed you too many times to count. He nods pitifully. "