@gjhiggins, will probably tell us the cause of this, but I think nothing big happened, really.
https://bchain.info/SLM/blocksEither a large amount of Slimcoin, previously not staking is now staking or someone has found a staking exploit. If it is the former, a natural event, then it will fade - the algos will ensure that. If it is the latter, an exploit, then it will unnaturally persist. All we can do is wait and see. (Please note, I didn't
write the Slimcoin code, I merely wipe an oily rag over it now and again.)
Blocknet (a Pivx/Dash/PPcoin clone) was hacked in early Oct by someone who discovered a way to exploit the staking mechanism for personal gain. Apparently Pivx had discovered and quietly repaired its code some time before. Any chance Slimcoin could have this very staking code defect that recently became known to hackers?