What would anda do if a giant ketam crashed through the roof?

I'd kick it.

"...I'm in some TV commercial, aren't I?
Maaaaaaaaaaan, I don't even like seafood."

I wouldn't give a shit because our flat is on the 3rd floor and the apartment has 6 floors.

Ah..... panic?

... Make Friends with it

Grab a bazooka.

I would anaylize how thick its exoskeliton is, and based on that, can my sword cut through it?
Chitlin is what it is made out of, which is the same material as the shells of clams. My sword would have little chance of cutting through it, in fact it would damage the blade. I would have to use a bludgeoning weapon to crack the shell first, which is something that I don't have. My best bet would be to see if I can hit a flater surface with dad's SKS rifle, but with the exoskeliton probably being about an inch and a half thick of chitin, I'm still skeptical of using the SKS.

Does anyone have a morning star? ._.;

Mmmmm...make crabcakes!

I live on the first floor of a 16-floor apartment building. The freaking ketam would need to crash through 16 ceilings to get to me. But if it does, I'd kill it, cook it, and announce to the whole building, "Free Chilli ketam for makan malam, majlis makan malam tonight!!!"

P.S. Chilli ketam is a Singaporean dish. Rawak trivia...