Mega absol is overshadowed by many other mega's with moor bulk and often higher attack. however mega absol has many toys to play with amd with a great SP atk it can surprise foes to try to wall it by nailing them with a powerful SP atk. all in all mega absol is not the most pwoerufl foe, but use it right, it will prove to be one hell of a monster.
252 Atk, 252 Speed, 4 Sp atk
item: mega stone
(pre-mega) ability: justified
move set: Night slash, Play rough
Flamethrower, sucker punch/swords dance
This is mega absol's pride and joy moveset. this is what he shows his friends when he brags about how awesome he is. altho the other mega evolutions are not impressed, if they saw it in action however, they'd change there mind. play rough and night slash give mega absol near perfect coverage. flamethrower suprises steel types trying to take a hit and or wall mega absol, hitting them on there weaker SP def side. the last option is all up to you. sucker punch nails the few pokemon who can claim to out speed and defeat mega absol in a single blow, however swords dance can be used to give you even moor physical power! driving fear into your foe, which may, if your lucky, pressure them to make poor choices.
Mega absol could go for a pure SP atking set, havign moves like ice beam and thunder bolt and the already mentoned flamethorwer. however it will miss out on its amazing attack stat, and is usualy not worth the mega slot, so this is not recomended. however it can be used for the suprise factor, nailing a surprise KO or two. A support set makign use of its magic bounce ability cna be used as an anti-lead, havign moves like thunder wave, perish song, and taunt. however mega absol's piss poor defenses make this a poor option.
Checks and counters:
Mega absol's ability to hit powerfuly on both physical and speshile attacks, and being imune to brun and thunder wave thanks to magic bounce, it is hard to take down. however Lucario, both mega and not, is a great check to mega absol, being able to smash it with a stab vacume wave or bullet punch to hit it before it can attack, and resiting sucker punch. Entry hazards are a great way of weakening mega absol, toxic spikes espeshily, as they are not blocked by magic bounce and getting absol badly poisoned severally cuts down its life span. trick room is a good way to deal wtih mega absol, turning its speed agenst it. coice scarf pokemon are good for defeating absol as they can outspeed and retaliate hard. any pokemon that can survive one attack adn hit back hard can be considered a counter, s they can deal massive damage if not take absol out, and then absol will fall to a easy revence kill. if all else fails wittle it down with repeated attacks.