Cool Whip and whipped cream seem to be two of the most commonly encountered substances in WAM. However, cleanup can be a pain and leave you smelling rancid for a while. I find while it's not nearly as tasty, shaving cream makes a great substitue.

It's got a very similar texture, and the foam seems to stay together longer. Further, an added bonus is that this substance has a history of being used in clowning, circuses, on TV, etc- which adds an element of historical value and tradition to the usage.

Can be found for less than a dollar at most grocery stores, allowing for a LOT of mess for minimal cost. Oftentimes, it makes for thicker pies, although mixing it in a bowl with a bit of water (add small amounts to start, then add more for desired consistency) will make for pies that offer more splat and drip. Added bonus: it washes away really easily, can be whisked off clothing if dry, and absolutely will not clog drains.

One downside to shaving cream is that most varieties of it will hurt if they get into your eyes. However, I have found that the sensitive skin formula usually does not do this, so that is the only formula I will buy.