98 idler puley bolt. really wierd

Ok so i have a 98 corolla. i need to replace the idler/tensioner pulley. The bolt is unlike n e thing i have ever seen thow. at first glance it almost looked like i had to us a "E" socket (inverted torx) on it. Its circular and has notches around it spaced evenley. i looked all over and it appears that later ones use T torx bits but have ever even found another with this type on it. does any one have any ideas o the matter. i will post a pic as soon as i can