You call that trolling?
THIS is how the professionals do it.
I thought that 4chan (may its name rot in the annals of history forever) was on an anti-epileptic streak awhile ago, having gotten tired of toying with Scientology? Their collective sense of humor would also match the MO: no actual damage done, just a mean-spirited prank.
I think causing a seizure qualifies as actual damage done.