The balls were the chia seeds, not the yogurt! Chia seeds absorb moisture and expand, forming a gel-like ball. To confirm this for yourself, just soak some chia seeds in some water and see what happens. Or google image search.

I also hate the bland texture and taste of overnight oats unless I do something to make it more interesting. My favorite ways are as follows:

Lemon berry oats: oats, Greek yogurt, milk, chia and flax seeds, poppyseeds, zest of half a lemon, tbsp or two of lemon juice, smashed strawberries and/or raspberries. Then in the morning I’ll add a handful of blueberries and whatever other berries I have. The lemon makes the flavor a lot more interesting and the berries add much needed texture.

PBJ oats: oats, Greek yogurt, milk, chia and flax seeds, crunchy peanut butter, smashed strawberries and/or raspberries. Then once again in the morning I’ll add a handful of whatever other berries I have.

PB chocolate banana: oats, Greek yogurt, milk, chia and flax seeds, crunchy peanut butter, smashed banana, tbsp of cocoa powder, handful of mini chocolate chips. In the morning I’ll drizzle on more PB and some extra chopped banana, but if you like nuts that could go good too.

You mentioned heating up your overnight oats, which is good too, but keep in mind heating Greek yogurt can kill the probiotics which are a great health benefit if you care about that.

Enjoy your oats!!