You can 'pause' and 'play' CSS animation by changing its animation-play-state property. Setting it to 'paused' stops your animation in place, until you change animation-play-state to running, for example on hover.
.animating_thing {
animation: spin 10s linear infinite;
animation-play-state: paused;
}
. animating_thing:hover {
animation-play-state: running;
}