C 126126 121 bytes
f(){i=0;char c[]="/-|\\";for\\|";for(;i<101;i++){printf("\rloading %c %d %% ",c[rand()%4]c[i%4],i);fflush(stdout);usleep(1000*(rand()%75));}
Ungolfed version:
void f()
{
int i=0;
char c[]="/-|\\";\\|";
for(;i<101;i++)
{
printf("\rloading %c %d %% ",c[rand()%4]c[i%4], i);
fflush(stdout);
usleep(1000*(rand()%75));
}
}
@Carcigenicate @ Mukul Kumar Did not read between the lines there, Thanks! :)