I was playing around with summon command and when I tried
summoning a skeleton with an enchanted sword my fps rate dropped

To reproduce
1. Spawn a skeleton with a sword (you can use this code)

/summon Skeleton ~1 ~0 ~0 
{
Equipment:[
{id:minecraft:wooden_sword,Count:1,Damage:0,
tag:{ench:[{id:20,lvl:2},{id:19,lvl:1}]}},
{},{},{},{}]
}

2.After that move close to the skeleton and try to 'walk' into the sword (so the sword will be in your character)
3.See fps drop

I attached a screenshot before and after the fps drop