If you are lucky, these can give you some great victories, definitely the main attraction. If you place three or more Clam Scatters anywhere on the reel, you will activate the reward.
This will give you the opportunity to choose additional free spins and increased multipliers on top of the basic 8 free spins and 2 multipliers. If you are lucky, you can add an additional 20+ free spins and increase the multiplier by about 15 times, although this is very rare. At this point in the game you should want to see the killer whales stack wild, which can really push up the rewards.