i have a plataform changing every 5 seconds, is a sprite whit 2 frames, frame 1 is just the plataform, in frame 2 is the same plataform whit spikes, if the player jump in the plataform on the frame whit spikes, the player gets hurt, thats fine, but if the player stay in the plataform whitout spikes and the frame change the spikes apear but nothing happen, but if i move the player the collision is detected.