You mean a pint of whiskey? Sure.
It’s called milk.
Going waaay out on a limb here…MILK!
For this you will need 3 items, one for each stage of the experiment - 1, bowl, 2, some milk, and 3, enough cereal to fill the bowl.
Now the first thing to do is name your bowl. Pick a good name, any name. Have you done that? Okay, good. No, don’t reveal the name you chose just yet. Now pour some milk into the bowl. What’s the name of the bowl now? How about… now? Or now?
Is the name still the one you chose? It is? okay. things are going well so far
For the second part of the experiment, you’ll need to name that cereal. Once again, pick any name you want…
It’s milk. Or dairy. Possibly cream.
Or more specifically, cereal. Even soy and rice beverages are called milk. I think it’s a fairly safe generic term. Is there anything people put in their cereal to make it wet besides dairy products (or ironically alcoholic things)?
I guess it’s closest cousins would be cold soup (is there a non descriptive term for that?) and some sort of dessert (most cereals seem to be highly sweetened).
I look forward to commentary by someone with a more expansive culinary lingua franca.
I guess we should also examine other ingredients that play the role of milk but in other contexts, like as a drink creamer, or in baked goods or chocolate.
Bailey’s Irish Cream over Lucky Charms.
A suspension?
I usually call it leche, sometimes I call it milk, but it never answers back. Very impolite, I say!
An ex-football player now football pundit grew up so poor that as a kid he put water on his cereal, and that ended up such a normal thing for him that he still does it to this day. I think it’s Cris Carter, but not positive. I imagine he’s not the only person in the world to ever do this, though his co-pundits looked at him like he had three heads when he admitted t.
Mælk!
An ex-football player now football pundit grew up so poor that as a kid he put water on his cereal, and that ended up such a normal thing for him that he still does it to this day. I think it’s Cris Carter, but not positive. I imagine he’s not the only person in the world to ever do this, though his co-pundits looked at him like he had three heads when he admitted t.
My mother has water on her cereal, because milk makes her feel queasy.
Maybe it’s a soup base? I mean, what you have when you are finished is pretty much an uncooked soup, right?
Uh? No it’s not, or at least not necessarily, and there is no such thing as “a soup base”.
I love these answers! 
My original reaction was “milk” followed by “wetting agent.” But I much prefer some of the other alternatives. Of the poll answers, the only one I was even tempted to use beyond “other” was “sauce.” But milk is not a suace without other stuff being added to it, IMVHO.
I’m tired of this motherfuckig milk in this motherfucking bowl.
I call it a bad idea, but I’m one of those freaks who likes my cereal crunchy, so I have my milk on the side.
I guess the OP’s brother is KennerTheWayWayLessThanGreat. Tell him it’s milk.
Milk. In a bowl. On cereal. For twenty minutes.
I think the OP asked the question wrong.
The milk you pour on cereal is just milk, period. The typical ‘pop culture’ question is “what is the leftover milk in the bottom of a cereal bowl called?” The mixture of milk, tiny cereal bits, and sugar.