The Spike is a useful little Microsoft Word feature. The Microsoft Word Help says:
To use the Spike, you remove two or more items from nonadjacent locations, append each item to the Spike’s contents [using CTRL+F3], and then insert the items as a group in a new location or document. The items remain in the Spike, so you can insert them repeatedly. If you want to add a different set of items to the Spike, you must first empty the Spike’s contents [with CTRL+SHIFT+F3].
Basically, you can go around selecting text and images and pressing CTRL+F3 to grab them from the page and stick them in the Spike. When you’re done, you press CTRL+SHIFT+F3 and it spits out everything you’ve put into it. It is also cleared when you do this.