The weapon of last resort, a power or tool meant only for if there are no options left. What do you have as your favorite? While Godzilla in the new movie only seems to use his atomic breath if his sheer muscle doesn't work, which would qualify it here, Gamera from the 90s probably has the best excuse I've seen for keeping his ultimate weapon as this. in case you're wondering, this is it:
Using this weapon drains Earth's life energy and makes conditions favorable to his arch enemy Gyaos, so he can't afford to lead with this.
Using this weapon drains Earth's life energy and makes conditions favorable to his arch enemy Gyaos, so he can't afford to lead with this.