While I do enjoy playing Terraria, which I am currently playing at the moment, almost finished with expert – hard mode, Stardew Valley 1.6 update has a nice surprise to what it seems like almost a collab to Terraria. In Terraria, Meowmere is a sword that can be crafted into Zenith (end game sword). In Stardew Valley, you have to jump through some monster-infested hoops in order to get the weapon though. According to this video: https://www.youtube.com/watch?v=3JQrJtxvneo, this will show you how to get it.

https://www.ign.com/articles/new-stardew-valley-16-easter-egg-lets-players-wield-one-of-terrarias-most-powerful-weapons