Sukuwareru Ramiris consists of 2 short episodes of 2 minutes each that feel like scenes they forgot to put in the anime somehow. The episodes happen in the middle of the 23rd episode of the first season of "That time I reincarnated as a slime" and can be watched at any point after the 23rd episode. In these episodes it is shown how Rimuru creates a golem for Ramiris. The significance of this is pretty minor but the golem will play a role in the second season and these two mini episodes get explicitly mentioned in a flashback which is pretty confusing if you haven'twatched them. The animation, voice acting and sound are all the exact same as in the main anime. Overall I'd definitely recommend watching this to anyone who likes "That time I reincarnated as a slime" and especially to people who just finished the first season so that they won't be confused about the origin of the golem.