Lemme help. Basic rule of thumb:
Offensive Pokemon such as Sharpedo can KO Golem.
Golem is vulnerable to strong attacks, and offensive Pokemon, such as Sharpedo, can KO it.
Golem is vulnerable to strong attacks, and offensive Pokemon can KO it. (Removed the list section, still have complete clause.)
If the such as list is an aside to the main sentence, (forgot the proper term) it must be comma'd. Try reading it aloud. If it's part of a longer sentence and you feel the need to pause before saying such as, add a comma.
Hope this is helpful :)