"tele-GC" is a strategy where you can make a colossus appear at the back of someone else's base (or basically anywhere on the map, including in the water)
You need an Aeon unit with T3 engineering (which means you need to get T3 on your ACU or someone needs to make a T3 HQ)
You need to use that unit to make an Aeon Quantum gateway (3000 mass)
You need to use the Aeon quantum gateway to make 5 aeon RAS boys (6450 each, which costs 32,250 mass)
You need to upgrade teleporter on all 5 RAS boys (75,000 mass)
You need to upgrade sacrificial system on all 5 RAS boys (750 mass)
Then you need to teleport all 5 RAS boys at the same time (teleporting costs 10k energy/second, doing it for 5 at once means 50k energy, -- so your team needs to have a lot of T3 power generators - 10 T3 pgens would cost 32,400 mass. It would be better to have at least double that)
When they appear at the destination, one RAS boy starts making the GC. Then all 5 of them use sacrificial system to build it basically instantly (which costs you the 5 upgraded RAS boys).
So you need to spend at least 110k mass for every tele-GC and that's on top of needing a big infrastructure with T3 tech and lots of T3 pgens