Multiple huge flies were in my house the other Sunday night:

1) One lit upon a leaf of my houseplant almost directly at eye level across from where I was sitting at my kitchen table, so it was like this big huge black speck on top of a thin green leaf that was like a very thin horizontal line to my eye, since the leaf was sticking out from the stem almost perfectly flat, according to my eye from where I was sitting.

2) Another flew around the bathroom when I was taking a bath, so I swatted it into the bath, and then it was in the water, struggling...  I couldn't get it out with my hand since to try to catch it, it'd just pour out of your hand on top of the water, so I used this metal anti-hairclog inset for my bathtub drain, and swept it through the water like a sieve, and I caught the big fly in it.  Then, I dumped the fly out on the side of the tub, and used the bottom of the anti-hairclog inset to crush it, making this rather surprisingly big moist crushing sound.  A single fly leg separated out from the crushed body on top of a small puddle of water, and it drifted away an inch or so, and just lay there in the water tension.