What is faster than a supernova explosion? Is a supernova explosion really fast or is it just fast, metaphorically speaking? Can you cite the fastest known phenomenon in astronomy (neutron stars, pulsars) besides supernovae in terms of explosions?

EDIT: yes, i mean the shockwave from supernova
I am assuming you are talking about how long the event lasts. See question on this site "How long does a supernova explosion last?". The answer is that if you are talking about how long it brightens then dims (its light curve), then it typically takes a couple of days to get to full brightness then weeks to months to fade. Core collapse can be a fraction of a second (keep in mind there are different kinds of supernovae).

The "fastest" pulsar found so far spins 716 times a second. If you really want fast, how about the standard for atomic clocks? The used transition is between two ground states of the element caesium that are very close together and lasts about $1\times 10^{-10}$ seconds. There are even better atomic clocks now.