Agarslant is a means whereby agar is created. It is also known as a TSI or Triple Sugar Iron Test. It is a process whereby agar is cooled in a slanted position.
Here's what happens: agar is mixed in a test tube with 1% lactose, 1% sucrose, 0.1% glucose, sodium thiosulfate, and ferrous sulfate or ferrous ammonium sulfate. This causes the agar to react in such a way so that it cools in a slanted position.