Frieren: Beyond Journey's End S00E11

Frieren tests a spell on the Hero Party that makes their sentences end strangely. They decide to have a contest - use the spell on everyone, and whoever laughs first must use the spell for a week. Himmel's sentences end in "nyan," Frieren's ends in "zoi," and Heiter's ends in "po." All three are able to hold in their laughter, but when Eisen speaks, his sentences end in "datcha" and the rest of the party are sent flying.