Thief
In Chip's Challenge 1, a thief, often referred to as a spy, removes all boots that Chip has when he walks on him, and acts as a wall towards monsters and blocks.
In Chip's Challenge 2, there are two types of thief tiles with different functions. The item thief (pictured with a red bandanna in the CC2 tile pack) removes all boots and tools from the player's inventory when crossed, while the key thief (pictured with a blue bandanna in the CC2 tile pack) removes all keys from the player's inventory. Both types of thieves also halve the player's bonus points upon being stepped on.
Also new in Chip's Challenge 2 is the ability to cancel the effect of thieves with a bribe. When the player crosses a thief while carrying a bribe, the thief will take only one bribe and ignore all other items, keys and bonus points.
Thieves act as walls for standard blocks, but ice blocks and directional blocks can be pushed over them. Sometimes, it can be to Chip's advantage to lose a superfluous item; see Elementary.
The two tile packs officially distributed with Chip's Challenge 2 do not use the same colors to portray the two thieves, which can be confusing. When using the Microsoft tile pack, the item thief appears in the original teal color from CC1 and the key thief appears as a red variant of the CC1 thief. On the default CC2 tile pack, this situation is reversed; the item thief has a red bandanna and the key thief has a blue bandanna. Further confusion arises in Lesson 1, where the hint text explains the rules for thieves in terms of the CC2 tile pack, even if the player is using the Microsoft tile pack.
Trivia
Microsoft Visual C++ v1.52 contains tools named Spy and DDE Spy. The icon of Spy is identical to the tile used in MSCC; DDE Spy uses the same icon, modified with a lightning bolt.
Spy About dialog
DDE Spy icon
In later versions of Visual C++ / Visual Studio, Spy is replaced by Spy++, with a modified icon:
Spy++ About dialog