why do vegetables spark in the microwave

Have you ever microwaved peas-n-carrots (the ones in the frozen veggie aisle)? Have you ever noticed that the carrots spark and/or flame after about 10 seconds!!?? Just the carrots, not the peas! I feel like I am watching Illuminations @ EPCOT or something. Blueish-white lights sparkle and pop all over the place! Little yellow flames streak up at various locations! It's crazy!!

When you take them out, some of the carrots even have burn marks on them! This is unfortunate because my two year old will not eat the carrots that have these small burn marks, so I have to go through and manually remove these carrots, or deviously scratch off the burn marks. What a pain! My wife and I have noticed this happening on various power levels, not just High, it just takes a little longer for the sparks and/or flames to occur.

We have even noticed this phenomenon on different microwaves (my mother-in-laws and various friends), so it's not something restricted to just our microwave. And again, we have not noticed this happening with ANY other veggies! Just carrots! It doesn't matter what temperature they are either, frozen, refrigerator temperature, or room temperature, the sparks and/or flames will always occur!

So, can anybody explain why this happens?
I've been making up frozen veggies in the microwave for LO lately. I did half a bag of peas and carrots the other day so she had them for lunch today. When I was heating them for dinner I heard this buzzing noise and turned and saw sparks all over them!

There were burn marks on them too! My first thought was something was in the veggies that I've been feeding her for 2 days!!!! But I also had green beans, from a whole different food company, so I tried to heat them instead and the same thing happpend! DH tried a 3rd thing (new bag) and the same thing again.

So we are thinking it's the microwave? Anyone had something like this happen? We've been in our house less than 2 years but the house was completed just over 2 years ago I(sat empty before we bought it). It's a built in one that also serves as the range hood. I had no problems that I noticed when I heated some leftovers for lunch today. I was sooo scared I gave LO something bad!!