Can I summon this mob? [closed]

You can not summon that mob. That command has a lot of problems. Arguments with no values, commas with no purpose, use of the Riding tag which was replaced in 1.9 with Passengers tag, specifying tilde notation with 0's.

The skeleton's equipment section contains no values at all.

Here is an equivalent command that does work:

summon skeleton ~ ~ ~ {Invulnerable:0,CustomName:Dinnerbone,CustomNameVisible:0,ActiveEffects:[{Ambient:1,Amplifier:128,Duration:999999999,Id:8}],Passengers:[{id:Slime,Invulnerable:0,Size:2,CustomName:Spikes,CustomNameVisible:0,Attributes:[{Name:generic.attackDamage,Base:30.0}],ActiveEffects:[{Ambient:1,Amplifier:1,Duration:999999999,Id:8}]}]}

Here is a picture of the results:

Edit to include requested information in the comment. Here is the mob with an invisible slime and a skeleton who doesn't move:

summon skeleton ~ ~ ~ {Invulnerable:0,CustomName:Dinnerbone,CustomNameVisible:0,Attributes:[{Name:generic.movementSpeed,Base:0}],Passengers:[{id:Slime,Invulnerable:0,Size:2,CustomName:Spikes,CustomNameVisible:0,Attributes:[{Name:generic.attackDamage,Base:30.0}],ActiveEffects:[{Ambient:1,Amplifier:1,Duration:999999999,Id:14}]}]}

Note: Decreasing speed of skeleton uses an attribute instead of an effect as there is a bug which prevents the slowness effect from working on mobs through summon command. The bug report: MC-32575 if you are interested.