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They catch on quickly however , and build some of the more exotic weapons of the game including the Electro-cannon , which emits electricity , much like lightning , to destroy targets ( Please note that the units do not need power like buildings ; they recharge themselves and are purely self-sufficient ) The Sonic-cannon , which emits a moderately powerful radial effect that damages all enemies around it .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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