Reserving Trap Drill
Excadrill @ Leftovers
Ability: Mold Breaker
EVs: 176 HP / 60 Def / 20 SpD / 252 Spe
Jolly Nature
- Substitute
- Toxic
- Sand Tomb / Iron Head
- Protect
In testing, this thing was very interesting. Originally this set was conceived to punish common switch-ins to Excadrill not named Corviknight. It does this job pretty well. It beats out or otherwise severely weakens Seismitoad and Hippowdon in particular. Toad especially, which is why I pair this set with either or both Zeraora and Band Dracovish. These two Pokemon deal with Excadrill's main counter, Corvi. In a symbiotic relationship, Excadrill deals with their counters as well, minus Ferrothorn (which isn't much of a counter anyway). Excadrill will always live a move from Hippo and Toad (if they lack investment), so you can tank a hit from them as a last resort as well.
The given EVs allow Excadrill to utilise one of its best assets, its speed, while maximizing Substitute bulk with 101 HP subs. The amount of pressure that Excadrill puts out means that most mons slower than it will switch out, allowing for free Subs on the switch into said normal counter. From here you have two options. 1) Toxic said switch-in to spread status, which is generally your best option. 2) Sand Tomb said switch-in, trapping it and slowly whittle it down, which is a solid option against Toad. If you predict Hippo's recovery correctly you can end up getting both Sand Tomb and Toxic on it. Not to mention, if you have already spread toxic to these Pokemon, this set works even better. Making Salazzle and Rotom-H carrying Toxic solid options for teammates as well.
Also works wonders against Bisharp, who will always Sucker Punch if you have not revealed your set. Even Sand Tomb, as piddly as it is BP wise, will do enough damage to Bish to be a winning matchup, even if it's at +2.
So it goes Sub on Sucker -> Sand Tomb for 36.1 - 42.8% damage -> Protect -> Sand Tomb again for the culture, or Sub if you're chicken (only chance Bish has to outpredict you). -> Protect -> Sub on Sucker again -> Sand Tomb if not dead (or if in sand range, Protect).
Iron Head is an option on this set if you want a pure Sub Toxic set, and don't like using an Excadrill walled by Clef.