  Microwave emission with spectral zebra pattern structures (ZPs) is observed
frequently in solar flares and the Crab pulsar. The previous observations show
that ZP is only a structure overlapped on the underlying broadband continuum
with slight increments and decrements. This work reports an extremely unusual
strong ZP burst occurring just at the beginning of a solar flare observed
simultaneously by two radio telescopes located in China and Czech Republic and
by the extreme ultraviolet (EUV) telescope on board NASA's satellite Solar
Dynamics Observatory on 2013 April 11. It is a very short and super strong
explosion whose intensity exceeds several times that of the underlying flaring
broadband continuum emission, lasting for just 18 s. EUV images show that the
flare starts from several small flare bursting points (FBPs). There is a sudden
EUV flash with extra enhancement in one of these FBPs during the ZP burst.
Analysis indicates that the ZP burst accompanying EUV flash is an unusual
explosion revealing a strong coherent process with rapid particle acceleration,
violent energy release, and fast plasma heating simultaneously in a small
region with short duration just at the beginning of the flare.
