A family of enemies in the Super Mario Brothers series. A Koopa Troopa is a turtle that typically does nothing but walk or fly around. Jumping on one won't kill it; the turtle will only retreat inside its shell. In the original Super Mario Brothers, you could kick the shell at your enemies. Watch out, because it will ricochet back at you if it hits something hard! In later games, Mario can disable a Troopa with a tail swat or cape swat. A fireball will take out a troopa completely, as will Super Mario World's Spin Jump.

Super Mario 64's Koopa Troopas are quite scared of Mario. They'll run away. If you catch up to the Troopa and stomp on it, you can use its shell as a self propelled skateboard-type thing which gets rid of every enemy in your path.

There are several varieties of Koopa Troopa:

Green Koopa Troopa

A Green is just dumb. It will gleefully walk off the edge of a cliff and fall to its death, no questions asked.

Red Koopa Troopa

A bit more intelligent, a Red will turn around at the edge of a cliff to continue patrolling an area.

Green Winged Koopa Troopa

These are just as dumb as the Green Koopas. The wings enable them to bounce up and down, and they require an extra stomp to get rid of the wings.

Red Winged Koopa Troopa

Reds are once again smarter than Greens. I wonder if this is pro-Communist imagery on the part of Shigeru Miyamoto. In SMB3 and SMW, these will actually fly back and forth to patrol a bit of sky.