The topic at hand here is basically to share the most ridiculous raid comps you've either used out of convenience, special mechanics considerations, or just for fun over the years. What fights made you take an abnormal number of healers, or way too many mages?
I'll share a few examples:
1) During Vanilla, my guild in mostly blues/greens would run ZG unless we had 3 mages for CC'ing trash. We also had 9 healers on our first Hakkar kill because our healers were sorely undergeared and couldn't keep up with the raid damage.
2) We had 5+ warlocks during our server-2nd Magtheridon progression during BC. Lots of fears and banishes to be had there.
3) I think we used 11 healers during Gurtogg Bloodboil progression at one point? We eventually toned it down, but we definitely had 2 healers per group at that point.