I just had a big flying cockroach and my boyfriend caught it under a jar but it has squirted some clear liquid

Question

onto the floor . What can this be? I have mopped up with boiling water but will do it twice if need be!

Answer 1

Either a defense mechanism or pee.

Answer 2

You did not say where you are located so I will describe the species Eurycotis floridana a large cockroach. It has a defensive spray that contains an odor similar to stink bugs.  This is a defensive spray which is effective on other insects and rodents that want to make a meal of the cockroach.  The fluid is also irritating to humans both to the skin and if breathed.  A boiling water mop up should have taken care of the fluid.  But it does have a high yuck factor so if you want to do it again, go ahead.