What is "so called spooky action at a distance"?

Quantum entanglement

//what is annihilation

The collisionion of particle with its antiparticle creates photon.

//what is pair production??

Creation of particle and its antiparticle from photon/energy. Have a look at Feynman-diagram 2 particles are created from photon Let's say Electron & Positron Muon & antimuon Proton & antiproton …

// conservations of.. Spin Energy

//What is spin here???

Angular momentum of a particle Spin conservation Before creation spin=0 After creation spin=0=+ve -ve Copenhagen: Wave function collapse!! Spin can be in any possible direction till you measure it. Superposition of all possible directions known as wave function. The very moment you measure it,wave function collapses (Dhadam…) and particle takes a particular spin. refer Schrödinger 🐈 cat example So you mean an-Observer-required!! Let's make a dry run here.. Name first particle as "ye"and another as "vo" Measure spin of "ye" ,it comes out to be (+ve) X Measure spin of "wo" ,(even if you don't)it comes out to be (-ve)X  So as to comply spin conservation You can measure it in any direction and you will get different direction each time according to instrument's measuring direction. Ohh stop it …

What is spooky about it??

There must be hidden variables that has been agreed to stick upon.. Yeah. That was very thought came in Einstein's brilliant brain Sorry to have to upset you But that's not the case here and very well experimentally tested Let me introduce a machine (for "ye") capable of measuring spin of electron in one of possible directions randomly And we have a replica of it available for "wo" particle . Hurray…. If agreed-upon-variables are the case then it must not change its direction when measured in same direction But it does change And at the same time a change is observed at another particle's spin measured with replica. So How does another particle know which direction it has to be in if both particles are separated by far enough distance(>10*3lacs km) Information travels faster than speed of light. So this bizzare behaviour is know as spooky (as called by Einstein).