Team

Composition

• Lvl 40 Excadrill, atleast 3/0/0 max moves, although I think it can be Lv30 too.
• You don't need anything else, but I brought a Zama just in case, and a Lapras to leave on the spot

Team Moveset

0.5s Mudshot for Fast,
Scorching Sands for Charged

Damage boosts

Max Mushroom : None

No friends needed

+10% from One Glove Helper, although I don't think it's needed

Boss

4* Dynamax Toxtricity

Boss Moveset

Acid Spray is necessary for Excadrill to survive long enough, although you can still do it with multiple Excadrills and maybe Metagrosses (Metagrii?) on your team.

Strategy

With Excadrill triple-resisting poison, while having a good attack stat, and doing double-effective ground damage, the team choice and boost moveset is inevitable. I have seen people do it with Metagross during Wild Area, but that does seem to be far slower.

With Wild charge doing 1/4 health of exca, that must be avoided at all costs, and power-up punch is single-effective, so avoid that too (or bring Zacian to tank). This Acid-spray and Discharge are the only two tolerable moves for the boss. My guy had somehow Acid Spray in both the spread and Targetted slots, but I am not complaining.

Since this a solo where the pace of boss attacks and max phases is pretty slow, it is the perfect situation to use charge moves in a Max battle. Since the battle is completed well before the desperation timer kicks in, if you find yourself in the situation where the boss has just used a move and you can easily fill the meter before the next move hits, take a moment to fire of some charge moves. It may not give you much energy, but the damage done is much higher. If you are pursuing this with a lower level Exca or with lower level moves, then that chip damage can add up and maybe save you a Max phase.