I have two GFCIs, can I connect the second GFCI on the first GFCIs LOAD? I know I can connect them in parallel, but I'm curious what this would do.
There's no point
First, a GFCI receptacle can protect regular receptacles downstream (that's why there are LOAD terminals on them downstream). Second, connecting two GFCIs in series creates a race condition if a ground fault is placed downstream of the 2nd GFCI -- it's indeterminate which one trips (it's even possible for both to trip on the same fault, as Tyson points out in his comment). Third, modern GFCIs require power to reset, so you'd have to reset them in order when they do both trip. All in all, it's a needless pain in the arse that's best avoided.