Edit round spike. Make it longer and add a head made out of number-of-sides x 2 vertices. Remove top faces, apply two new faces (actually two faces made out of a number of triangle faces, depending on the number of sides again) to the head you've just made.
The top face is going to have the same normals as the one you removed, The bottom face will have the same normals, but multiplied by either one of these three matrices (depending on which way the spike is oriented):
| 1 0 0 |
| 0 -1 0 | <-- rotate around the x axis
| 0 0 -1 |
| -1 0 0 |
| 0 1 0 | <-- rotate around the y axis
| 0 0 -1 |
| -1 0 0 |
| 0 -1 0 | <-- rotate around the x axis
| 0 0 1 |
Or if you have 3ds max, just make a new model :P.
(bottom line: how do you intent on making a "new ra2" if you can't even do this stuff..?)