/setblock ~ ~1 ~ minecraft:mob_spawner 0 replace {SpawnData:{id:"minecraft:skeleton",CustomName:"Level 2 skeleton",CustomNameVisible:1,ArmorItems:[{},{id:"minecraft:chainmail_leggings",Count:1b},{},{id:"minecraft:chainmail_helmet",Count:1b}],HandItems:[{id:"minecraft:bow",Count:1b},{}],Attributes:[{Name:generic.followRange,Base:10}],ActiveEffects:[{Id:1,Amplifier:0,Duration:1999980,ShowParticles:0b}]}}