t += 0.03;

offset_y = sin(t) * 3;
offset_x = cos(t) * 2;
x = base_x + offset_x;
y = base_y + offset_y;

image_xscale = 1 + sin(t) * 0.03;
image_yscale = 1 + sin(t) * 0.03;
image_alpha  = 0.9 + sin(t) * 0.1;