Chaining Connections The LEGO 2x4 brick is somewhat of an icon of LEGO, and the majority of official LEGO bricks can connect back to it. However, the number of bridging bricks required can vary, depending on the piece. Some pieces, like a 1x1 Round Tile, can be connected directly to it; however, others, like the Technic Axle 32, require additional pieces (in this case, the Technic Brick 1 x 2 with Axle Hole) to bridge the gap.

The piece I can think of that requires the most of said bridging pieces to connect back to a 2x4 is the body of the Bohrok Canister assembly, which requires 4 pieces to reach the 2x4: the lid, the hanger clip, a Bohrok ribcage, and a 1x2 Brick With Pin. My challenge is, can you do me one better? What piece takes the most bridging pieces to connect back to a standard 2x4, and what is the chain required for it?

Rules:


The piece must be official LEGO; no messing around with off-brand pieces with absurd new connection types.
All connections used must be legal; no strapping things together with rubber bands and calling it good (that would take all the fun out of it).
There must actually be a method of connecting the pieces together; pieces like the ball used in Scorpion Palace or any of the BIONICLE canisters without built-in studs are just cheating.
This answer is based upon the wrong assumption that Technic chain links and conveyor-belt links (a.k.a. bulldozer chain links) connect to nothing except each other.
As remarked by Ivan Sanchez, this is contradicted by this set, which uses a connection between a conveyor-belt link and a standard arm/rod.

Assuming that these chain links only connect to each other, the only way to connect them to something else, is wrapping eight of them around a standard 16-cog gear. (You can also wrap six of them around an 8-cog gear, but I would not consider that a robust and intended connection.)

Finally, the gear can be connected to a length-3 axle with stud, which in turn can be connected to the bottom of the 2×4 brick.

For bulldozer chain links, this looks like this:





Now, it depends on how you interpret the challenge: You need nine other pieces to connect the chain link to the 2×4 brick. However, many of those pieces are again chain links and there are only two pieces between every chain link and the 2×4 brick.