One of the largest terrestrial true bugs in North America, this bad boy (or girl) can reach up to 1.5 inches / 38mm in size (although subjectively it seems much bigger in person!). The wheel bug (Arilus cristatus) is an assassin bug, which means that big pointy bit on the front is in fact a weapon, and this insect is “well noted for an incredibly painful bite when disturbed or nonchalantly handled”. This one politely let me get within about two feet for its portrait (this image is heavily cropped).
The wheel bug gets its name from the ridged “wheel” on its back. It is actually a beneficial insect which eats a lot of pesty things like caterpillars — even densely haired ones like the highly venomous puss caterpillar. It is also one of the few predators which can eat the brown marmorated stink bug, which is a serious (and stinky) pest of many human crops.
The one pictured above is probably female (they are larger than the males, with rounder abdomens).