I spawned 250 enemies without calling any functions to move them (but they had the ai controller). The fps went from 70-75 to 25. I think it happened because each mannequin has around 10k triangles, so 250 * 10000 = 2.5 million triangles. I know I have to make a character with 2k triangles or so. Btw I will not spawn 250 enemies in my game.
I also spawned 250 moving enemies and the fps were 8-10.