Evolution Chart

You can feed your Slimes evolution froot during the stream, and it will raise their stats. If their stats get high enough, they can evolve into 3 different stages! They'll also increase in size a bit when they eat. (This size will reset after evolving. After you evolve to stage 3, you can keep eating froot to increase their size further).
This is a chart of the Slime Evolution Forms that Guardians have discovered so far!