There are at least 8 artists with the name Serum.
1) A Miami-based MC:
Whether commandeering a spray can and an outline or rocking a mic and a crowd, Serum manifests a rugged, overpowering and commanding vibe, all his own. However besides destroying walls and microphones, his specialty is actually feasting on wack MCs. Serum (together with his boy Wreckognize) is among Miami's most notorious battle MCs.

Read more about Serum on Last.fm.