Weird science!

Didn't get to finish the haunted house area due to two factors.

First there was an extra level where I had to get the map back from some pirates. It took a few tries but it had a neat weird metal gear sold feel sneaking around the bad guys.

Then one of the levels of the haunted house area has this weird laboratory where I could not for the life of me figure out how to solve it. Basically all I have available is a bat/umbrella and a centipede/saw that I can combine into a potion that makes me shrink, but I need to get to the snake so I can become invisible. Whenever I shrink down the snake eats me, and I can't figure out any way through the level.

I'll give it a few more shots tomorrow before I break down and look up some hints on line...