I am an absolute newbie at Sonic GDK, and the closest thing I've found to the enemy option would be the basic destroyable. However, those don't accept skeleton models, and the meshes change when you hit them, so...What do I do?
I know you said elsewhere that you fixed this, but I'll answer anyway. Badniks in the GDK editor are made up of two actors. The first, the BadnikPawn, contains information for the Badnik such as sounds, damage points, particle effects, the skeletal mesh used, and so on. The EnemySpawner is what actually spawns the Badnik that you specify. Each Spawner is tied to one BadnikPawn. The Spawner actor has variables such as patrol paths, the physics used (does the Badnik fly / swim / walk?) and when it is spawned. Both of these are found in the Actor Classes in the Content Browser, SGDK>Invisible. Custom behaviour requires Kismet knowledge, and how to use "empty" variables, and is a whole world in of itself, so leave that for now. Play around with the editor and see what you can do.