Strange Matter:

Strange matter is a hypothetical state of quark matter only formed in neutron stars that converts all other matter into strange matter. This may result in the release of a lot of energy (read radiation) and the conversion of our suneverything into strange matter.

A cloud of strangelets (strange matter particles) colliding with the sun would be pretty terrible. Since they are purely hypothetical, the speed and pattern of the sun being converted to strange matter would be open to interpretation.