That Event horizon is so cute

But I don't know how to play him well, bot lane, or top lane trolling everyone from rushing to top (much like Anivia wall)?

Veigar can go both top or bot, it is entirely up to you. Though if you go bot, you will most likely stalemate the lane until you have DFG and Ult to combo people to death. Either way i suggest CDR+Spell pen because he has really good damage, but atrocious CDs. He is more useful top where he can make enemy casters think twice before engaging and provide an AoE stun, and then late game he can generally disintegrate just about anyone, but then promptly dies to anyone with a gap closer or ranged cc.

My recommended skill ordering
Top: QWE
Bot: Can you harass or farm Q safely? Yes:QWE, No:WQE

A lot of skill is require with Veigar as positioning is important and hitting people with the edge of the Event Horizon then pressing W>DFG>Q>ULT>Q as fast as you can, then getting the **** out of there. He is not a forgiving champ to play on Dom but very rewarding and fun. Expect to die a lot and get guff from teammates, but hang in there. I have made people taste the rainbow with my Leprechaun skin and loved every minute of it, win or lose.

Definitely not one of the easier champs to play on dominion. He has some of the most amazing burst damage ever though. Nyx covered everything pretty well. I like taking him top, personally, because with the champs people play bot lately, it's just painful.

Veigar's Event Horizon doesn't stun friendlies, btw. I mean, if you were using it to block the enemy I wouldn't exactly calling it trolling. It would be more of "doing your job".

Anivia wall is trolling because it reroutes your pathing and makes you run backwards.

Rushing top with Veigar and dropping a stun could be useful but there is the problem of being stuck playing Veigar for the rest of the match.

your teammates will likely rage at you if you play him. i wouldn't necessarily mind losing if the veigar on my team has that awesome skin