The wr3+4 oki trap
Bob has a subset of combo routes which end in this sequence:
f1 uf1+2~f BAL 1 iwr3+4
The iwr3+4 here does not combo. Rather, what happens is that the BAL 1 knocks the opponent into a FDFT position. wr3+4 happens to be a very plus on block move with a lot of active frames that hits grounded.
Thus, if the opponent stays on the ground, they will get hit by a wr3+4 done quickly enough. Too slow and wr3+4 will fly over their heads- hence the need for iwr3+4.
If they try to back quickroll, a quickly executed enough iwr3+4 will clip them before they can block. Since they're in a FDFT position, they cannot kip up.
Their only remaining option is to techroll. If they do this, they'll be invincible during the first few active frames of wr3+4 and will be forced to block it meaty- meaning that, at MINIMUM, Bob will be +15 on block and point blank.
Not even Yoshi can interrupt the ensuing mixup between b1,2 and db3. Most characters cannot interrupt a quickly executed hellsweep followup. b1 is an unparryable elbow, which means that even at -15, chars with 2 frame punch parries will not be able to parry it. They must take the mix.
Generally, combos ending in this setup sacrifice anywhere between 5 to 10 damage compared to the max damage routes, but luckily, the BAL 1 ender is wallsplat-friendly. The rule of thumb here is that the earlier in the combo the tailspin occurs, the less damage will be lost by using this setup. Recommended launchers to use this ender from are uf4, cd1, and ch (1,2,)1+2.
The Bob Infinite
Bob has three launchers which launch the opponent in a backturned state- db1+2, ff1+2, and BAL 4. Normally, off the former two launchers, Bob will follow up with a tailspin move immediately to turn the opponent around for a max damage combo- but he doesn't have to. In the case of BAL 4, he has no choice but to combo them in BT, but that's not necessarily a bad thing.
To capitalize off this situation, do a juggle with the tailspin left until the end, followed by a dash up 1+2~f BAL 4. 1+2 spikes, so they'll be forced to wake up in a FUFA position. Should they do anything but stay grounded, BAL 4 will launch them, letting you loop into the same combo route. This is an infamously effective strat at lower levels of play, where people have been known to lose entire rounds off a single BAL 4, hence the name "The Bob Infinite".
The counterplay is easy- just stay grounded. Bob's best answer to this is to do BAL 3+4 or BAL into crouch cancel b3 for flipover okizeme, but these is a fairly hard read on his part as both are launch punishable mids. If the opponent eats the BAL 4 or BAL 3+4 in the open, they can then wake up safely and reset to neutral; b3 will allow Bob to keep his offensive momentum but does much less dmg than BAL 3+4.
On a sidenote, these three launchers are also Bob's main way of setting up his Rage Drive into BAL 3+4 combo ender. This ender operates on the same principle, but with the ensuing effect of massive damage rather than looping okizeme.