The effect of the card is as follows:
Bench Shield
Trainer - Pokemon Tool
As long as the Pokemon this card is attached to is on your Bench, it can’t be damaged by attacks.
To use a Pokemon Tool, attach it to one of your Pokemon. It can’t be attached to a Pokemon that already has a Pokemon Tool attached to it.
So would this protect a claydol from Gengar's trick room?
Bench Shield
Trainer - Pokemon Tool
As long as the Pokemon this card is attached to is on your Bench, it can’t be damaged by attacks.
To use a Pokemon Tool, attach it to one of your Pokemon. It can’t be attached to a Pokemon that already has a Pokemon Tool attached to it.
So would this protect a claydol from Gengar's trick room?