What kind of tool do i need for this?

Grind the head off.

Looks like a torx.

You would need a hollow head torqs,,never saw one like that before. Has to have a hollow bore like a nut driver,,,sorta with outer torqs drive. Unless that center piece pops out somehow. or is this a rivet type fastener. grinding prolly quicker.

It's a tamper proof torx screw and it will be hard to find a socket head for it. Grind it or sawz-all it off.

That looks like a T-27 Button Torx ® w/pin. You are not likely to find a socket at the Big Box. If not first try a cold chisel & Hammer
http://www.hudsonfasteners.com/sec/sec_tx_bhpsts.htm
.

Looks like a Uni Star Head. Try this

http://store.solar-electric.com/43661.html

It also resembles a Scott's Stabilizer Security Bolt. But I don't have their address.

I found a bit for that at my local True Value a few years ago. It's a bigger store with a great inventory, so I dont think most hardware stores will have it. Def not at a big box.

I have used a dremel and ground off the nob in the center. Use appropriate size torx after that.

thanks for the quick replies. yeah i figured it was some kind of tamper proof thing. reminds me of some of the ones i've seen in public restrooms to hold stalls together. i decided to just grind them off, some of them look pretty rusted so i would probable end up needing the grinder anyways.

thanks again!

Mike

Yes, this is a tamper proof torx head. I have one in my tool box.
These are used in some automotive applications also.
If can find a auto tool dealer such as Snap-On, Mac, Matco any one of them should have your bit to remove this.
--also depending on the quality of the fastener you might have luck breaking off the center pin with a punch.

harbor freight FTW.

I would run into them from time to time when having to take burglar bars off windows to replace them and found it just as quick and easy to pry the whole unit off with a flat bar/crow bar and hammer. If the surrounding brick/mortar/stucco was delicate then I would grind the head off to prevent damage.

Security Torx. Lowe's carries them. I saw them yesterday when I was there plus I bought a set from Lowe's a couple years ago.