What exactly happened when I added KOH to hydrogen peroxide? I recently added a potassium hydroxide, $\ce{KOH}$, pellet to a small droplet of hydrogen peroxide (30 %), $\ce{H2O2}$. You could clearly see the potassium hydroxide dissolving in the droplet when instantaneously the solutions began to fizz strongly (boil and/or release oxygen gas, I'm not sure) and release a lot of heat.

I'm not sure what happened, but I've got a few ideas of what might have happened:


There is some kind of reaction between the $\ce{KOH}$ and $\ce{H2O2}$.
The $\ce{KOH}$ released a lot of energy when dissociating into the aqueous solution and then boiled the water, maybe reaching the temperature of  150.2 °C in which it also triggered the decomposition of $\ce{H2O2}$ into water and oxygen gas.
On Wikipedia I read:  


  The rate of decomposition increases with rising temperature, concentration and pH.


So when $\ce{KOH}$ is dissolved, the solution has a high pH and this might trigger the decomposition of hydrogen peroxide


I did notice after a pH test that the plastic lid on which I had condensed some of the evaporated water had a very high pH, so this would most likely contain some dissolved potassium hydroxide.

In case a reaction happened, what could that specific reaction be?
According to THE HOMOGENEOUS BASE-CATALYZED DECOMPOSITION OF HYDROGEN PEROXIDE J. Phys. Chem., 1961, vol. 65 , pages 304–306:

$\ce{H2O2 + OH- &lt;=&gt; HO2- + H2O}$ 

$\ce{H2O2 + HO2- -&gt;}$ [6-membered ring with 2 "H"s bridging 2 "O-O"s, with another H bonded to one of the "O"s] $\ce{-&gt; H2O + O2 + OH-}$


  It is clear that the rate will go through a maximum
  when the peroxide is 50% ionized, that is
  $[\ce{H2O2}] = [\ce{HO2-}]$.