A method, proposed by Ryan Vigil in late 2017, based on tripod and sledgehammers. It most likely has a lower move count than CFOP. It can be used to generate a good skeleton for FMC if steps are done loosely. Also the name is cool. Vigil has used this for his main method ever since its development. As of April of 2018, he averages 30 seconds, and has a best time of 17.63 with the method.
1. build a cross. Very intuitive
2. build F2L-1. (Note: this step can be done as the first step, using blockbuilding)
3. finish tripod. (this step is meant to be done intuitively.)
4. place the remaining three edges using up to 2 sledgehammer algorithms. (Note: parity may occur, and in that case, use a J-perm to swap the two edges
5. finish the remaining corners using either hexafusion or one of the 62 algorithms.
Solving corners in sledgehog is a very interesting step, as there are 4 possible types of cases that can be encountered. the first and most straightforward type is where one corner is solved, and the other three are cycled. there are 36 different algorithms in this set.
the next type of case is one where all the corners are placed, but some are rotated. for this case you may just use beginners corners or use advanced algorithms.
the 3rd type of case is where no corner is in the right place. this alg set has 27 algorithms, but you may just use a triple sledgehammer to reduce it to the 2nd type of case. Not all of these algs have been generated.
the final type of case is where one corner is placed, but it is rotated. for this step you use a combination of (R' D' R D) (or a sort of warped sexy move) and U to both orient and permute the remaining corners. This process is call hexafusion because if (R' D' R D) is done 6 times, it will solve itself. If the U and U' moves are placed correctly, you can solve all the corners with the six "sexy moves". Hexafusion can be difficult to wrap your head around, and can only really be learned by practice.
this method has potential for blockbuilding, adding freedom into the solve. A lucky scramble can get you nice blocks, and therefore quicker solves. All of the 3 corner algs are 12 moves or less, therefore being very fast to learn. In addition, during the sledgehammer stage, additional sledgehammers can be used to force a corner in, giving you a better corner case.
when you are using this method, lookahead is very difficult. It is very hard with a quick glance to tell the difference between a double corner swap and a hexafusion case, not to mention recognizing the corner swap cases.
also, there are more rotations with this method, as corners can position themselves on any of three axes for a case. the best fullstep time achieved to date with this method is 17.63. But, Vigil expects times to come down as more people learn this method.
Is this a ZZ variant?
Several people seem to confuse this method with ZZ. However, these methods couldn't be further apart. The major difference between the two is EO. Sledgehog does not use any form of EO, where as ZZ does it right at the start. ZZ does a more traditional last layer, whereas sledgehog doesn't really have a LL step.
This method was developed independently of Ryan Heise's Tripod method, and is similar only in the construction of tripod. But even in that, Heise's method was developed for blockbuilding, and Vigil's sledgehog was designed with F2L in mind. However, these methods could be mixed in matched to cater to each scramble.
It can also be compared to CFOP, because both rely on F2L, but sledgehog leaves a slot to work with.
Sledgehog also has a subset in common with Anthony Snyder's method, as the last three corner subset is used in both.