iPad acting very strange (HELP!)

Hi guys,

something very strange is happening to my iPad 2 and I'm hoping someone could help me out.

So my iPad was working fine few hours ago, and had approximately 50-60% battery left. So I put it to sleep by clicking on the power button on top right, and did my business. After few hours, I tried to turn on the screen as usual by clicking the power button but it won't turn on. So I tried long-clicking because I figured somehow it turned off, but it didn't register. I tried clicking the home button but nothing.

So I plugged in the charger (despite knowing there was battery left) and the iPad turned on as if it was completely turned off (and asking my passcode and stuff). When I put the passcode, it opens but the battery says 100%. When I unplug the charger, it goes dead again.

Even more weirdly, when I keep charger plugged, it stays awake for a minute then completely goes dead again. Then after few seconds, the apple logo comes up (as if rebooting) and turns on again. The cycle continues.

I did not drop it or anything, it was just sitting there, and it worked perfectly fine up until now. I'm very confused why it's acting this way.

Is this hardware malfunction, plain and simple? Should I take it to the apple store and have them fix it or replace it?