What is this insect? Looks like an ant/beetle in my house?

It's long about 4 cm long, dark coloured, it looks like it has 2 bodies and 2 tails at the bottom. Looks like a weird type of ant? I've seen a few in my kitchen?? Its not a cockroach or beetle, it doesn't have an oval or round body it tapers in like a wasp and then another part of it body that tapers again into two tails! Freaking me out!!